IAC Chapter 107 is a chapter of the International Aerobatic Club (IAC) which is, in turn, a subsidiary of the Experimental Aircraft Association (EAA). Membership in IAC Chapter 107 therefore requires membership in the IAC, which requires membership in the EAA. You can get information about joining those clubs at their respective websites:
You can also join both organizations online at the IAC website.
IAC Chapter 107 dues are $50 per year. If you join mid year, they are prorated for the remaining months and everybody renews in January. We are not currently set up to take credit cards so the simplest way to join is to come to one of our meetings. If you want to join but can't make it to a meeting, contact our president, Jeffery Poehlmann (firstname.lastname@example.org), to get more information about joining.