Market size estimate for a small racquet sport

Estimate how big the US market is for a minor racquet sport such as squash or racquetball.

A few hundred million dollars a year is a sensible order of magnitude. Estimate participants (say $1\%$ of $330$ million, about $3$ million players, many of them casual), then annual spend per player on equipment, balls, court fees and club dues (perhaps $100$–$300$ dollars), giving roughly $300$–$900$ million dollars. Segment by casual versus committed players and state which revenue streams you are counting.