Since the first Indy 500 was IIRC in 1911 your question about availibel kits is pretty broad. I don't think that there's any recent car available in plastic. Monogram had a fifties era Indy car in it's re-release programs a couple of times that builds up into a pretty nice looking, though somewhat simplified, version of a car from that timeframe.
I remember ERTL re-releasing one of the mid seventies MPC Indy car kits in a three car combo kit in the mid to late eighties along with, I think, the Lotus Ford and that mid-fifties roadster. Maybe a search on the "-bay" could net you one of those. It would get you a good spread of styles and eras to begin with.
I think that there may be some smaller scale stuff in resin or white metal also and I remember some really nice 1/18 Die Cast that was also available in kit form a few years ago. The name of the company escapes me but they also had some really nice pit and garage stuff too.
I really like that old Monogram kit and as a beginner it would make a nice starting point, I think. The newer cars are very fiddley and delicate compared to the "dinosaurs", what the "funny car" (rear engined car) drivers called the roadsters of the fifties and early sixties but I liked'em.