With so many app being published everyday, it’s has became very difficult to get you app notice.
without constant marketing your app will fall from the app-store ranking within 1-2 weeks.
thankfully there are ways you can make money from your old apps and games.
By selling your app source code
Fallowing are the site where you can sell your games
here your can sell your app code (android ,ios) to multiple user
price range around 10-20$
here you can sell your published app store app.
you can place your app for auction and there by you can achieve maximum price for your app
The Marketplace where to Buy and Sell Ready Made Apps and Games for iOS and Android | Reskin and Launch an App in no Time
just like chupamobile , another website where you can sell you app source code
- scirra store
if your app is made using construct 2 engine , you can place your app code into scirra store
here you can also sell game asset music plugin ,etc