How do national rental companies like Avis compare to local car dealers

I really like old school cars like corvette 1990 zr1 which I spotted at a local car dealer. But firstly I’m not sure do they offer rental services. I believe they mostly do. Secondly, in terms of price, do those local businesses have a friendlier total price compared to national companies? National companies usually as far as I know, include insurance in the price, and the total price for a normal casual car is like 60 per day. Thank u.