Specific days throughout the year at both hurricane harbor and great adventure hey have member events where members get free food, ERT, and 1 free pin for each event. The dates for the events are here, closer to each event they update it with a detailed schedule. 3 events (opening, Wonder Woman, and bizarro) are already passed so you can’t get those pins, but if you go the rest of he dates you can get the rest of this pins for free. I’m 90% sure the dates are in the correct order of the pins, but don’t quote me on that
Heres the link to the information about the pins: https://m.sixflags.com/greatadventure/special-events/member-collection-pins