I am not a big NASCAR fan but maybe this will help you.
You can rent scanners at the track. I don't know how many they have but try contacting the speedway for info:
http://www.lowesmotorspeedway.com/contact/overview/
There are also vendors not affiliated with LMS that rent them, such as TrackScan in the white trailers with the blue/black/yellow logo. I can't remember any of the other names but they aren't hard to find.
Also check Radio Shack. This one is recommeded a lot and is a lot cheaper in the long run:
http://www.radioshack.com/product/in...tId=2180625&cp
There are a lot on eBay as well.
Have fun.