Switching iPhone 4s carriers?

So I found this iPhone 4s a few months ago. I don't know what carrier the person had but can I just get Virgin Mobile as my carrier?

Wow you got lucky finding that… Anyway, you can find out what carrier it was by going to the Settings app, then going to Cellular Data, and attempting to sign in, you will see the carrier logo.

If the logo is Verizon, you're attempts will fail, every time. If it is At&t, you're in luck! That carrier can be easily switched, just call virgin mobile.

Verizon iPhones only work on Verizon, sprint iPhones only work on sprint. But if it is an AT&T iPhone you can unlock it and use it with any carrier that uses SIM cards… But I'm not sure if virgin does.