How much does it cost to unlock an iPhone 4s? - 1

The phone is with AT&T and I want to go to simple mobile

I bought an iPhone 5 last week, i was looking for a way to unlock it that i found some websites doing that, prices were so high ( $70-$180! ) but i finally found an unlock company doing that for just $25, i ordered the service and they unlocked my iPhone in about 20 hours with my iPhone imei number, no jailbreak, no softwares. It seems they are official apple unlockers doing unlocks through apple.