Can I unlock my iPhone to use it on virgin mobiles network?

My iPhone is on the sprint network and my bill is almost 250 a month for only 2 phones is it possible to unlock my phone and use it on the virgin mobile network?

My sister had an at&t one and had it unlocked to use on t-mobile's network. So i'm pretty sure it's possible.

No its not possible.

No it is not possible.