Honestly, the price of an entry fee is almost irrelevant compared to travel, lodging, food, parts, tires, fuel, oil, etc.
The clubs should not low-ball entry fees to try to get more entrants. That puts their program at too much risk. Charge an appropriate amount. The club needs to make a profit so they can have a cushion in case of rainout, etc. In general, our entry fees are lower than most other types of racing at the same track.