If you ever find yourself abandoning your side projects, then give http://sideprojectors.com a go. A plenty of people have sold and bought side projects. It's been my .. side project for awhile. :)
Also, do you "vet" the submissions? Ex: Here's a SnapChat clone for sale for just $15. There's even a comment from a user asking if price is real. https://www.sideprojectors.com/project/project/2571/flash-ch...
And here's another one. I saw a Craiglist meets Instagram iOS App that is on App Store, and seems like a real lot of work, that is for sale for just $50. https://www.sideprojectors.com/project/project/3424/instagra...
And your search is not working. I searched for "Poshmark" to locate the above link to the 'instagram-mets-craiglist-style-app' App project and I get 0 results (the word Poshmark is in that listing)
Here's the URL https://www.sideprojectors.com/project/home#search/all/all/a...