I've never heard of a credit union charging its own members to accept coins. That's the kind of thing I'd raise a stink about at a members meeting.
My old credit union in Queens charged non-members for coin-counting, but not members. The one I have now apparently won't take coins from non-members at all (because a member's account number must be on the wrapper, just in case the count is off), but they don't charge a fee.
Even TD Bank (the only bank I know with coin counters in every branch) doesn't charge a fee for their depositors. Once in a while I use their machines if I'm going to be near one of their branches. I give them my parents' account number and tell them that I'm running an errand for them. They've never raised an eyebrow.
Rich