This last week I took my annual trip to the US to visit family. Like always, while I was there, I made sure to hit up the used game stores and buy games that have never come out in Japan—i.e. Dead Space, Command & Conquer Red Alert 3, etc. Despite having lived in Japan for so long (eight years now), it still surprises me how different it is buying used games in America as compared to Japan.
When buying used in Japan, a game is either rated as "like new" or "junk" and is priced accordingly. Of course, all that it takes to put a "like new" game in the "junk" category is a missing instruction manual or damaged box. If there is any actual problem with the game—like a scratched disc, for example—a used game store won't even buy it back. Yet, just to prove the disc is up to snuff, you must look at and approve of any game disc before the store will sell it to you. Thus, when buying used in Japan, you can get even the newest games dirt cheap if you don't mind a lack of instructions or the original case.
Also, due to the fact that renting games is illegal in Japan, most stores buy games back at a higher price than in the US. When I sold back New Super Mario Bros. 2 right before my trip, I only lost about $10 total, putting it about even with a two-week rental in the US. Buy back prices will also tend to stay much higher for much longer in Japan.