They do not repair them at all.
They replace them for the Out of warranty price:
If you own an iPhone that is ineligible for warranty service but is eligible for Out-of-Warranty (OOW) Service, Apple will service your iPhone for the Out-of-Warranty Service fee listed below.
|iPhone model||Out-of-Warranty Service|
|iPhone 4, iPhone 3GS, |
iPhone 3G, Original iPhone