Slightly higher than mormal. Last that I paid for a just an alignment check/tire rotation it was $70+fees+tax 6 years ago using a coupon. When I buy from tirerack and send the tire to a store, they charge roughly $13 additional per tire for mount/balance. In your case, it was just check/correct tire balance.
What really bugs me most and what I look for now for tire work is whether I have to wait. Back before I knew better, I nearly always had to wait 1 hour before a tire shop even starts work. Now I'm willing to pay smaller good mom/pop shops for tire work if I can just drive right up and by the time I sign papers for work, my car is already being lifted.