Just start going around to garage sales. I've already been finding DS/3DS/PSP games or Xbox 360/PS3 games in the $1 range. Really just a single 3DS game that I can think of finding, from everything else nothing much really that good overall though. I'd rather be finding older console games or PC games. I honestly pass on most of these $1 games as they're mostly near worthless junk and usually aren't worth the effort to sell, and aren't worth playing.

I actually know someone who recently found Xbox One and PS4 games at a thrift store, apparently all lousy crap though.