The group I joined southeast kayakers used to just ask for a dollar when you went to meet up for a paddle to help cover stationary admin costs.I don't know about other groups and how they work.
Hi Red rose I am a member of a kayak canoeing group on meet up.It cost me nothing to join they organise different trips for all abilities group sizes are limited .I haven't been for a paddle for while but they are a friendly group of people.