i tried to mount mine myself .... but had no luck, so I took my wheels off, and took them to a local shop.
they charged me $20 per wheel, plus one needed a tube for $13.
If they have to take the wheels off your bike, they will most likely charge you by the hour as well.
look for a small shop, dont go to a big megastore, they have too much overhead to cover.
and yes, they are screwing you on the price of the tires. if we can get them for $30 some dollars online, they are getting them even cheaper from their distributor.
I agree Run ...