So i've Played only one r&c game before, i think it was called quest for booty or something like that. I remember having fun with it but it was really really short. Was that the normal length of a r&c game?
If so then i understand why they are only asking $40.
Quest For Booty was a very short game. Most R&C games are many hours long (8-10 hours depending), especially in Challenge mode (You get to replay through the game on a harder difficulty with your weapons you already have and get to buy some new upgraded ones to level up) which can nearly double the length of the game, as well as doing side missions.
I recommend picking up the other 2 main PS3 R&C games, Tools of Destruction and/or A Crack In Time. They can be bought very cheap these days or digitally/PlayStation Now. You can get the HC collection of the PS2 games to, the first game has aged a bit in the controls department but still all a good play. AVOID All4One, Full Frontal Assult, you can get Into The Nexus if you really dig the series, its somewhere between Quest for Booty and a normal R&C game in length.