Never pay more than the original retail price to play a game. If you don't have money coming out of your ears, just emulate. There's no glory in going broke trying to have a legit collection that no other living person will see, much less admire. The purpose of video games is to be played, not sealed away in xenon gas. If you want the real hardware experience, fine, get it while you can, but flash carts and the like are the way to go with those. That way, you get the real hardware, the games play perfectly, and you don't spend the price of a used car on building up a decent library.