In my High School days, my friends father, took the family car in for wiper blades. They charged him $30 to install(in 1986). He didn't realize the local auto part store, puts them on for free(or you can just do it yourself). The dealer probably just plugged it and re-filled with air. I had one mechanic tell me, he marks the rim/tire with chalk and mounts the tire in the same spot(to avoid balancing). My local Mavis Tire plugged my slow leak for free. I was amazed, the guy spent almost 15min working on it. I tipped him a $10-spot.