I actually never played before recently. I hardly played PS1 (N64 was at the time and still is 1000 times better).
I got it off amazon for like $2-4. It's cool. Surprisingly it has some cool features I wish even GT5 had. Mainly the ability to race modify any road car, and concept. Plus it has some car models that GT5 doesn't have and I have no idea why the cars were dropped from GT after GT2.
The physics aren't very good admitedly but it's fun, and even if you only played GT3-GT5 like me, it has a lot of nostalgia to it.
I'd say it's worth it even at $7. I doubt you'll be dissapointed. I'm sure you're not expecting much seeing as it's a PS1 game so you should be happy with it