You will find games for these older systems, really any Mac will end up a collectors item, and there will always be a 2nd hand market for this stuff.
EBay really, you should find some good stuff on that. If you are just looking to get some games to play on it, maybe look for an unboxed collection, as they tend to be pretty cheap. It only get's expensive with this stuff when you look for boxed games in good condition - loose disks tend to be pretty cheap considering. The cheapest option would be to look at burning your own disks somehow.
I am the one who knocks...