Check Best Buy, if there is one in your area. They have the Greatest Hits for PS2 right now, 2 for $35 or $19/each.
That way you can get titles like God of War and Shadow of the Colossus on the cheap.
God of War is one of the games that people will be talking about 20 years from now...well, maybe moreso the publicity stunt Sony pulled for the sequel in Europe last week, lol.
Yeah, it's got everything you could want in a premiere action title. It's a major achievement.