Can an iphone 4s from sprint be unlocked?

My mom's friend had an iphone that she wasn't using anymore so she gave it to me to use on metropcs

Yes it is possible, try the website that my friend has used it to unlock his iPhone for permanent. It seems they are official apple unlockers.their price was about $25 and they did a remote unlock by getting the iPhone imei number. They unlocked my friend's iPhone in just 12 hours.

take a look at their website: http://officialappleunlocker.com/