I always keep my ear to the ground around flea markets. I am gunshy about purchasing used optical disks online. I've just had too many bad experiences with them. But when I can inspect them upfront before laying down my cash that's another thing entirely. Sometimes people running game stands at a flea market will have newer stock that they didn't bring because it wasn't "retro" enough to be cool yet. Ask around and see what you find. Even if you don't find games, flea markets are weird and fun places to poke around. You won't have wasted your time.