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 5 $229 iPhone 4S $199 iPhone 4, iPhone 3GS,
iPhone 3G, Original iPhone
A $6.95 shipping fee will be added if service is arranged through Apple and requires shipping. All fees are in U.S. dollars and are subject to local tax.