That would be hard to do, I mean I come from a very poor family. We honestly struggled to pay the $40 yearly fee to play sports at all. My mom actually had to save up for it like she was buying a new big screen TV.
Let the boys and girls wrestle each other and see who has the most fun and ends on top.
Local sponsorships and fund-raising efforts are ideal for cases like the one you describe. And for specific cases involving poor kids on teams where most members don't have a problem paying the cost, people like me would be more than happy to provide financial support in any way we could.