Is the iphone 4s carrier unlocked for cricket?

I bought the iphone from cricket about a month ago i'm starting to not like there service and simple mobile were i live is pretty good. So can i drop cricket ( stop paying the bill) and switch to simple mobile? My 4s has a sim slot but there's no sim in it? Plus if its not carrier unlocked can i unlock it to use simple mobile?

Buy a simple mobile simcard, put it in the phone, unlock the phone, and activate it.