FWIW, I wouldn't pay seven cents. I can't imagine taking a bike to the shop for a flat tire.
If you DO do that, though, $7 seems reasonable to me. The mechanic's time, shop time, tools, overhead etc. all add up. Last time I noticed, two of our local shops wouldn't patch at all. They charged the price of a new tube plus $2, I think it was, for installation (may have gone up--that was at least three years ago). One of the owners told me if he billed what it cost to patch, it would cost more than the tube anyway.