I am searching for an application to manage my game collection either free or paid. If there is one for Linux that would be great. Also I have a barcode scanner so supporting it will add points. Any suggestions?
What you mean by "managing"?
Most barcode scanners work by emulating a keyboard, but what you will use that barcode for? There is no easy way to obtain game details' from its barcode.
Anything that you can is possible to do (search for a game, insert a game, add info, get automatic updates and info, scan a game and search it, and many many more...).