Why would I pay $100 to test n' tune when I can run for $5,000 to win for that?
$35 is plenty for a test and tune. Most tracks' weekly test n' tune is cheaper than that. Guess it costs 5x as much to have a class car go down your race track... One thing's for sure, at $100, the track will receive $0 from me.
Supply and demand. They charge $100 because enough people actually pay it. Don't stand for it, and the price will come down.