Can i buy an iphone with straight talk?

I want an iphone because i'm sick of androids. But i have to stay with metro pcs until i'm on my own. Can i go to the store and buy an iphone with straight talk, then after the 45 dollars is up activate the phone with metro pcs, or can i just buy the iphone with straight talk and forget about the card and just activate it with metro pcs? Any other suggestions are welcomed.

Straight Talk will not unlock their phones to be used with another provider. It says on the back of the box that if you are purchasing the phone to be used with another provider do not purchase the phone.