Can I unlock an iPhone to use overseas?

My coworker was going to sell me her old iphone to use overseas. I want the iphone because I have heard many great things about using them while studying abroad in europe (free texting in hotspots, facetime, etc.) My friend had a different provider she purchased her iPhone with (I use Sprint). I was wondering if there was a way to unlock the iphone 4s so I can use it with my provider overseas. If this is not possible, are there any other phones that offer similar benefits. I would love to be able to face time my boyfriend while abroad!

Yes, you could get it jailbroken. This would allow you to use it with any phone network across the world

Www.freeiphone.asia/

( works worldwide)