Steve, I rent cars quite frequently.
Use this website to figure what the bottom dollar price is for the days that you need the car http://www.carrentals.com/
Then use a service such as priceline to undercut that price by a few bucks.
Last time I was in vegas, I ended up with a PT cruiser vert for 17 bucks per day. Anything out of Buffalo airport will be around 30 bucks a day at the cheapest list price.
I usually stick with the economy cars due to the gas mileage, and cheap factor of them.
As far as I know they only look for alcohol offenses or other major vehicle offenses. Points such as speeding aren’t a problem, unless its a certain amount. Check the rental websites for more details.