Restrictions on awarding cash prizes to High School Debate?

I am going to host a message board based debate with a cash prize for the winner(s).

The debate will be open to anyone, but I want to make special invitations to high school and college debate teams. Professional political workers will also be invited.

The prize will be between $50 and $500 and based upon the voting of the participants.

Are there any laws I need to worry about for awarding cash prizes to high school or college students for such a contest? Anything like “losing amateur status” if they win a big cash prize? Do I need to call the prize money a scholarship?

Thanks!

Matt