Private leagues question

This is my second year with Supercoach and am thinking of joining some leagues with a monetary prize. Curious what the norm is for making payment? I've found a league but don't actually know anyone in there, the guy running is asking for the payment upfront and then he'll give the code to join. Does that sound right? How do these things typically work?

Sorry if this is a silly question, just don't want to be ripped off