I`ve been buying sealed ps2 games on ebay for a while now, and there are plenty of bargains to be had. But I`ve also ran into a few pitfalls and these are the situation that one should avoid :
1. Pictures can be deceiving . Many sellers, especially the big power sellers who have multiple copies of the same game use stock pictures, and don`t post a picture of the actual item. They will use a stock picture of the black label version and send you a "greatest hits" version of the game.
2. Some sellers are genuinely clueless as to what "Brand New" and "Factory Sealed" means. They cannot differentiate between a reseal and a legitimate ps2 seal. The real ps2 seal has y-folds in the corners, and that is nearly impossible to duplicate. This process is also used by xbox and gamecube, so as to prevent tampering with the disc that`s inside. Every ps2 game has been released with y-folds. One exception is the games that were packaged as a set (like the pac-man set), but these games should not be sold individually. The pac-man games were released individually with y-folds. A big problem on ebay right now is that there are sellers selling used games that have been resealed, and of course these games don`t have y-folds. And there are games that are new, but at some time the original plastic seal was damaged, and they were rewrapped.
3. There seems to be 3 main possible versions for any given game, and the original version (1st edition) is the one with the white strip on top. The game may have been published later on without the white strip and that version is called the reprint. Big sellers who have multiple copies of the same game usually sell reprints. The reprint may be a genuine ps2 game and may be factory sealed (y-folds) but its not the 1st edition so it is worth less. And finally, there is the "greatest hits" version which is easily recognizable by the red label that says "Greatest Hits" on it. Its a genuine ps2 game, its got y-folds, but it will always be less desirable in a collection. In conclusion, when you are buying a game for your collection, you want to get the 1st edition which is the one with the white strip on top and this is why you want to see pictures of the actual game and not a meaningless stock picture before you make a purchase.
So far I`ve had a few problems (3 different sellers sending me used games that had been resealed) but I took it as a learning experience as I did not request pictures of the actual item before buying. Now I only buy from those sellers who post actual pictures of the games and I only go for the "white strip" versions.