I cracked the glass on my iPhone last week. The Apple Store wanted $199, for the repair, which would end up being $217 after tax. That seemed pretty steep considering I paid $199 for the phone (with a two year contract), and the same phone is $99 now (with a two year contract).
I sent a text to Tom at Jet City Devices in Ballard and set up an appointment for that afternoon. Once I showed up he had my phone glass replaced in a few minutes, with a 1 year guarantee, for $95 including tax. Jet City Devices has a shop in Chicago as well.