If you're looking for something to zone out to, this is it.
It's not a particularly great racing game. The AI drivers all suck, and the "story" is so bad it's funny. However, it does sell the fantasy of owning expensive supercars very well, just by throwing easy money at you and giving you literally thousands of miles of road (and offroad paths) to wander around on.
As a game, I would rate this 6 or 7 out of 10. As a plaything for clearing up my head and just relaxing, it's an 11 out of 10. I dumped 800+ hours into the first game (back when I didn't have a job) and spent something like 150 hours on this in the first year. If you're just looking to drive and you don't care much for realism or physics, this is a steal even at $50 and a mindblowing deal at $5.