Now, you know you have spent a lot of hours on building your project which means it's likely you solved some problems that other people with similar interests and projects may have faced or are still facing. If you already have a solution for for a problem, try selling it.

If you aren't able to sell it and If open sourcing is possible for that part of your codebase that solves a problem then you could try getting sponsors/donations/etc and GitHub recently introduced that. This will allow you to showcase your skills and worth for your "code". I say "code" because that's all that it is to me. I don't know what it does, I don't know how maintainable it is, I don't know if it's well tested. It's very hard to sell just "code" based on "work hours".

Now using this approach, you might just be able to establish some worth for your whole project by advertising it as, Uses the popular, scalable and battle tested "your open sourced code" - also by me

Now I'm not sure how useful these things might be to you. Just my two cents. Good luck.