The cheaper it is, the faster your driver gets injured in the event that something happens.
Check Speedway Motors and other bigger stores for close outs on last years model numbers, big savings to be had.
I shop around for a lot of our parts and equipment, but usually the cheapest I find is at Turk Brothers Racing, www.tbrwins.com
Decent quality and a good price. I usually get my order in 4 days.