all iknow of is Ebay, autotrader. there are a few others but not too familiar with them. If i was in your shoes i would get a 350Z not just because its a Z, but you can get either a brand new or a almost brand new for great prices and they are great cars, i would avoid a early 03 though they have some problems go for a 04 and up. But a NSX is going to be alot older more prone to little things breaking. Also if your getting a loan i couldnt imgine how much a loan payment would be for one of those. Good luck