How to sell the rights of a software project to another developer/entrepreneur?

I have one product I started developing earlier this year which I haven't touched in several months now. At some point I began to realize that as a single developer, I'm simply not prepared to dedicate the time and resources to testing to make it as good as I want it to be.

It is a fully functional freeware app that has been downloaded over 1,000 times. And it has the potential to be sold as a professional product. How do I find another company or individual to hand this off to? I'd like to sell the full rights to someone who is truly interested in taking it to the next level. It seems like I've seen a website dedicated to this sort of thing but I can't remember what it was.

You might find someone interested at Flippa or SitePoint's marketplace. You could also contact competitors directly and see if they are interested.

Several people I know sold their company on eBay.

I know that sounds ridiculous, but it's not...

The problem when you say you're not willing to spend the time and resources to turn it into a production product is that anyone looking to buy it from you thinks if the idea is that good, surely you'd want to keep a financial interest in it. If you really believe in it, find a small company where the product would be a good fit (and that's a lot of google hours of researching, to translate) and give it to them for a profit cut. If you don't, you'll find other people don't either.