What is your go-to site for hiring freelance resources to build your startup?

The best ones that I have used are as follows:

O-Desk: https://www.odesk.com/. This is good for more complex tasks that are still relatively cheap to implement.
Fiverr: https://www.fiverr.com/. These are small jobs that cost $5 bucks per gig. Good to get small stuff done fast.

I hate to say this, but this is how I found a great outsourcing partner in India. I spoke to my friend who recently moved to the U.S. from India and ask them if they wanted to be my "interpreter" to find a good outsourcing partner for additional tasks. They actually knew people doing exactly what I wanted to get done and they were able to connect me to a great small firm in India that has great and ambitious contractors for hire for only $6 per hour.

Sometimes the best way to do it is ask an Indian or Chinese friend :).

This doesn't specifically answer your question, but a lot of people steer clear of "the big sites" like eLance or oDesk because they're worried about getting low-quality code back or having other issues with the deliverables.

If the kind of work that you need done is fairly vanilla web development (ie not scientific computing, super high performance stuff, specific algorithms, etc) I've found that you can actually get high-quality code back from the freelancers on those sites for very cheap.

The important thing is to be very specific with them so there's as little ambiguity as possible. You'll need to write detailed product and technical specs yourself, as well as create mockups of what the pages should look like. These are the components that require the most design and careful thinking.

Once you've fleshed all of that out, it's easy to hand off to someone cheap and and have them crank through it quickly. They'll usually appreciate that their project is so well defined.

So while there are definitely some horror stories that come from the "big" freelancing sites, they can definitely be a great way to hire freelance resources, if you know what you need to have built very specifically.

I can only talk about Odesk which was good, Mokriya I heard fantastic things and a friend used augmenteddevelopment.com and have good references.
I also know some freelances that are really good (but DM me)

I being an app developer get hired more via my own site (www.agicent.com) than upwork (I've to bid a lot to get small of work on upwork). Startups find us via social forums like this, or via google search or meetups and then discuss their App ideas and then we offer our best app development services and if all goes fine then its development.

If you are a freelancer and you wish to use freelance resources, these sites will surely help you out:
1. Upwork: Upwork is one of the top-rated websites in the world when it comes to freelancing and freelance jobs. It has about 50 lakh registered businesses and 1.2 crore registered freelancers for more than 30 domains. The jobs range from writing, designing, marketing, sales, customer support, ethical hacking, accounting, and much more. Upwork charges about 20 percent of the total fee you would be charging for your services for the first five jobs, after which it charges about 5 percent of the fee. While a few argue that there are hidden charges, there are hardly any valid Indian stories to back this claim. Upwork is mostly for top-rated professionals and getting a profile approved can be daunting. The key to getting approval is being genuine in your application.
2. Fiverr: Fiverr was founded in 2010 on the concept of buying and selling of freelance services globally, starting at just $5. The prices would go up depending on the complexity, skill, demand, and the duration of the job. It soon grew in popularity and is now actively used by millions of users to offer and use freelance services in more than 30 different domains. Fiverr has a “gig” culture where you, as a client, post a gig for a certain requirement. A freelancer with a relevant skillset can bid for this and "get the Gig". It works extremely well for beginners of different and vocational skill sets to start searching for gigs in domains such as writing, dancing, editing, painting, and coding, among various other niches. Though simple and easy to use, Fiverr has always been controversial due to its low pay rates and professionals globally complaining about the quality of the work being delivered. Be sure to bid well and deliver quality work while you are at it.
3. Freelancer: Freelancer, as the name suggests, is most straightforward and is used by a lot of IT freelancers, majorly in India, the UK, the US, and Pakistan. It has a presence in about 247 countries, and a total user base of 24 million. One can find a wide range of freelance jobs on this site: coding, web development, graphics, accounting, data entry, writing, sales, and marketing. From time to time, Freelancer hosts a range of bid competitions apart from the usual gig bidding. There are substantial cash prizes for winning these competitions. While jobs on this site are genuine and up to the mark, Freelancer has a history of getting into legal trouble over how it handles personal data.
4. Guru: Guru.com is one of the oldest freelance platforms on this list. It was founded in 1999 as eMoonlighter.com and then rebranded as Guru. This platform allows users get paid not just by the hour or by the tasks, but also based on milestones and recurring payments. While it is still among the top websites, the competition has certainly made headway in recent times. This, actually, is good news if you are a freelancer as it means that you have comparatively lesser competition when compared to giants such as Upwork or Fiverr. However, there is one major drawback - how the website handles client accounts and user funds. There have been reports of account suspensions, and it is important that you proceed with proper caution.
5. People per hour: As the name suggests, People per Hour is an online marketplace for hiring talent on a per-hour basis. It also has a unique collaborative feature. Collaborative streaming of projects allows freelancers to pool in human resources and work as a virtual team to finish their goals. This not only helps freelancers do a better job, but also helps them grow their network. People Per Hour, apart from helping create a peer network, helps you build good client relations that may help you secure future jobs. Like Fiverr, this site does not deal in localised currency. While Fiverr deals in dollars, People Per Hour deals in pounds and pays out in the same currency. This might be a minor inconvenience for freelancers taking up international projects.
6. UrbanPro: UrbanPro is an online tutorial portal, which has registered and verified teachers in every domain possible. Here, one can learn anything from basic mathematics to playing the cello. If you are talented and capable of teaching people of any age group, you could sign up and start teaching them online or offline too. All you need to do is create your profile, bid for the best, have a conversation with your would-be student, and start your classes.
7. Broxer.com: Broxer is the perfect way for beginners to start their freelancing careers. One can start offering services such as writing, graphic designing, coding etc., for as low as Rs 250 per hour. Signing up and getting this experience can also help you build a better profile for high-end freelancer sites.
8. Listverse: I am going to start this with my favourite one. List verse is a website with great content. But the website is content-scarce and ready to pay any writer $100 for any new list. The condition is simple - keep it original. The best part about this is that there is no specific topic, and you are also not given any specific guidelines. Choose any topic under the Sun and generate engaging yet fact-rich content, and you are good to go. There are no upper limitations to the word count but keep the list to at least a minimum of 10 per article. By personal experience, I would say that each article should easily cross a 1,500-word mark. The one and only major roadblock for is the payment. You need to have a PayPal account as Listverse does not allow payments on any other network. So ready your listicle, sign up for PayPal, and you are good to go.
9. ContentWriters.com: Next on this list of writer-centric freelancer websites is ContentWriters.com. This is an enterprise-level content writing services firm dedicated to providing high-quality content. The best part of working with Content Writers is the huge knowledge repository you will be exposed to, allowing you to climb up to the next level of your professional writer journey. Content Writers is a serious website and accepts only professionals; the pay reflects that as well. Also, you would be working with some top professionals, which would enhance your knowledge. Apart from signing up as a writer, you can also sign up as an editor too. This has its own perks and large pay cheques.
10. Crowd Content: Crowd Content is an online content writing services firm that, even with its team of in-house writers, heavily relies on outsourced content. Though a small website, Crowd Content offers two more things.
Writer’s University: An online knowledge repository where you can further sharpen your skills or writing content/copy.
Pricing Table: This can be leveraged and stated as your standard pricing once you have a substantial experience working with their formats and if you want to branch out. Crowd Content has an application limitation and uses this for filtration. But you can apply and await approval.
11. Freelancewriting.com: Established in 1997, Freelance writing is a dedicated platform for freelance writers to bid and get the best available writing gigs in their area of preference. All you need to do is sign up and create a profile to get started. The payout at Freelance Writing is neither too high nor too low but is competitive with most freelance websites. But the best part are the writing competitions the website holds. These will bring out the best in you and keep up your writing spirit while winning you more projects and cash prizes. You can also access the best of writing resources available on their website to amplify your ability to write better.
12. Kolabtree.com: Kolabtree is a medical and scientific freelancer platform where you can hire and consult with top-level scientists and science professionals all over the world. While this is not the place for regular content writers, it is a good platform for someone with a science degree in almost anything. There are projects that require medical writing by professionals and if you are someone with a bachelor’s or a master’s degree, or a PhD in the relevant projects, you are up for a bid. Bids and projects range from chemistry, biology, and doctorates to over 2,400 different fields of science. It is possible to find PhDs and veteran scientists from every discipline.
13. Publoft.com: Publoft is a marketing services start-up dedicated to providing start-ups and businesses with inbound marketing strategies. The freelance programme at Publoft promises great prices for your content with biweekly pay-outs. Editors at Publoft will handle your work and help you with any necessary corrections and clarifications. Your payout is likely to increase as your association with the website grows. The start-up is at a nascent stage and promises a great journey as it grows.
14. Behance.net: Starting off our list for creativity is Behance, an online platform owned by Adobe for showcasing and discovering creativity. Famous for the talent it curates and projects, Behance is the perfect way for designers to not just showcase talent but also find great opportunities. One can also find full-time and lucrative opportunities from around the world. However, given the discovery nature of the platform, the pricing of the projects is entirely client dependent. But there is no bidding on this platform.
15. 99Designs: 99Designs is an online creative marketplace that works as an intermediary for designers and clients who post requirements about logo designs, websites, book covers, and pretty much anything related to visual designing and editing. With over 1.7 lakh designers from over 192 countries, it is highly trusted by the creative design community all over the world. The USP of 99Designs is its highly famous design competitions where competitors bid and compete for projects and clients. Clients can either browse and pick profiles that they find interesting or just create a contest where contestants can enter and try to win the project. The pricing is non-uniform as this is a competitive platform and you must be extremely talented and competitive to rank on top.
16. Toptal.com: A pure IT and tech talent-centric platform, Toptal is a dedicated community website that caters to coders, web developers, app developers, and UX/UI designers of the world. Apart from coding and tech development projects, it also acts as a platform for non-tech IT jobs such as project management, finance, accounting etc., Great for networking and pricing, Toptal contributes immensely towards the development of its registered talent by offering many tutorials and research blogs. However, getting in is tough. As the website suggests, it only accepts only the top three percent of the cream crowd. Screening is done rigorously through a series of filtrations of your application.
17. Codeable.io: Now this one is an interesting website. Codeable is a web platform that is dedicated to WordPress developers around the world. This simple platform ensures that clients need not search for individual developers and check their credentials. An algorithm does all the job of searching if you enter your requirements. As a WordPress developer, all you need to do is create an impeccable profile, bid correctly, and deliver satisfactory work. This ensures you end up ranking for every search related to your expertise and skill set. Codeable pricing follows a no-bid strategy. You can set your own price; this essentially eliminates pricing competition and puts the focus on talent and intuition.
18. Dribble: Dribble, yet another platform owned by Adobe, is a community for creativity. Users can post questions, answer queries, ask for help, and do much more. Think of it as the GitHub for the creative community. Clients can post their requirements to find the right talent for their requirement on Dribble Jobs. This is a brilliant opportunity that can be leveraged if you are a seasoned designer. Like Behance, Dribble has no bid culture. The pricing is either task dependent or client dependent.

19. Envato Studio: Every WordPress developer and design professional knows this vast repository of creative themes, but did you know that Envato has a separate platform that serves as a marketplace for freelancers? The Envato studio enables clients from around the world to search and hire not just talented WordPress developers and designers, but also online marketers and app developers.
Besides if you do have any questions give me a call: https://clarity.fm/joy-brotonath