I agree on the 'low cost to join' comment. I pay $90 annually.
Our club has coordinators for running, walking, cycling, swimming, and tris. Each coord has designated workouts throughout the week. No matter your schedule, there is always a workout to fit.
We have open water swim sessions on Friday and Sunday mornings. The coord puts bouys in the water and we have anywhere from 20-50 each time.
We also have different group training programs for an additional cost (TRI 101, Marathon 101, IM/Half specific courses for a group with an upcoming race), as well as out of town trips to train with other clubs, or with Dave Scott in Colorado.
There are constant speakers/info sessions on everything from stretching to fueling to recovery. Members that are in the medical field are always offering body fat testing, massage, etc.
But the biggest thing about our club is the people. We've got the greatest, most diverse membership, and we have a blast. That part just kind of happens, I guess.
Good luck.