Keeping it simple is usually better. How about this: Give the tow boat provider $5 per pull that his/her boat tows (per pull, not per skier) plus free tournament entry for one skier. The comp'd entry fee is not cash out of pocket to the tournament sponsor. Travel and hotel, if any, can be negotiated as necessary. Many clubs can put up a promo operator in a member's home. Most personal boats used in tournaments will be local. Promo boat operators likely will have travel expense that SHOULD be considered, especially if the promo person would NOT have attended the tournament anyway. The hardest part of this plan is keeping track of the number of pulls for each boat. $5 per pull is not a magic number - it could be another number - but $5 seems reasonable for all. Efficiency and common sense can keep tournament costs reasonable for skiers, boat owners, and sponsors.