I want to build a website like growthhacker.tv -- the platform (with similar functionality/UX), not the business/concept.
If you have zero resources, this is exactly how I would proceed. Especially without technical skills.
1.) Go to tomodo.com
2.) Skin the growthhacker.tv site. with your own graphics.
3.) Manually reach out to people on letslunch.com who are developers and show them mockups of your site that you've built on tomodo and ask for advice. Do this 3 times and collect their feedback.
4.) Keep talking to developers until you find one that is as amped about building your site as you are.
5.) If you book me, I can walk you through more trips and tactics as a non-tech person.
The short answer that I'd give to a non-technical person would be:
Try services like oDesk to find someone/freelancer who has the skills to build the website for you. Take some time to read their reviews and look at their work.
This route is great for those with a small budget and little technical knowledge.
It's never easy to understand how much something will cost because there are so many moving parts, phases, non-technical costs, and degrees of completion that need to be considered.
My advice to clients is usually to take discussion to a higher level and consider things like:
1) Do you want to replicate growthhacker.tv exactly? Or are you just wanting to make a business similar to it, and you want to get to an MVP with similar functionality? They have probably invested a lot of time/money into refining the application with promo codes, analytics, and lots of admin things that you can't really see. Do you want all of that, i.e. the cost to build a mature business, or are you just interested in what it would take to build the core technical system?
2) A lot of your cost will hinge upon your experience and what you can bring to the table. Do you have any experience with project management, design, ui/ux, etc? What level of service do you need?
3) It's also a good idea to look at this in reverse. Instead of 'how much will it cost?' you can consider 'how much do you have to invest?' - then get an idea of what is possible with your current resources.
A good technical person/consultant should be able to describe some ball-park prices based on various scenarios so you can get some context. There will really never be a 'cost' for something like this, but you should be able to get a sense of what possibilities exist and the general investments required for each.