Birthday party dilemma

My almost 3yo loves the trampoline place. So I would like to have her bday party there. The package is $199 for 10 kids. All the kids are between 3 and 6 yo.

The problem is that they charge for the parents if they jump. $23 p/p.

5 or 6 parents will be an insane amount of money that I can't afford right now.

Idk what to do. Do you make them pay if they want to jump? Do you let them know somehow that just kids jump?. Half of the kids are cousins and the other half friends from school.