About 75% of all games I've ever purchased were used ones. Where I grew up there was (and still is) only one little shop that not only stocks brand-new stuff, but also buys and sells used games, DVDs, consoles etc. - works like a charm. Whenever I'm on vacation at home I make at least one stop there. Functional games at great prices, and it's a hell of a lot better to pump money into vast businesses like MediaMarkt (not that I don't like them, it's just that they have enough money as it is).
Btw, they even have great prices on new games. I was prepared to pay another whooping 70 euros for GoW2 since it didn't get released in Germany and I usually have to order from Austria. But lo and behold, the guy at the shop had some copies anyway - for 49 euros. Beat that, big game retailers! ^^