Zero $.
Seriously, start with assumption that you don't have any budget and come up with the best possible strategy with that limitation. You now have your MVP (minimum viable "product" or in this case approach).
Given a small budget I would never jump immediately into paid media. I've built two successful programs, one at IBM and another at HPE. Both with triple digits ROI. I never would advice with "start by buying ads".
I would start with what value can you provide your prospective customers through content? In other words, what can you teach your prospective customers that will help them do their jobs better and build trust.
Here are some tips that might help you:
1) Leverage freelancer networks like Upwork for a lot of your work. Everything from Wordpress theme customization to design to writing/editing content.
2) When available use solutions already out there. Don't hire an agency to build you a blog, get a template from a site like ThemeForest.net and have a freelancer help you customize.
3) Use GA (google analytics) -- no brainer
4) Use some of your budget on critical tools like marketing automation (Pardot, Marketo, etc), social media (BuzzSumo), etc.
5) Integrate your marketing automation with your CRM. This piece is critical as you want to be able to measure things from end-to-end and see what's working.
6) Don't just give media companies money instead growth hack. There are a lot of ways to generate attention and traffic without paying for it directly. You can reach out to some existing groups and communities and do partnerships. I can help with this or happy to share what I've done.
7) Spend a good chunk of your budget towards content creation both articles/blogs and long-form content (ebooks, reports, etc). Focus on inbound vs outbound.
8) Use the paid media budget to amplify content and offers that are already working. Don't put money on unproven content and/or landing pages.
9) Optimize like crazy. Test everything, make a bunch of mistakes quickly and be super scrappy but data driven.
I hope this helps, it's a lot easier to share more on a call but regardless I hope there's some value to you and others with the quick tips above.
BTW I'm brand new here but love the idea of helping others solve challenges. I'm currently managing a multi-million dollar marketing and content program with hundreds of freelancers and 10 employees for a Fortune 50 company.
Cheers!