S.B.
I got my son a Tracfone. It was on sale for $15.99. You add minutes as you need to. No surprise bills. If they use up their minutes, you add more, but my son never overused.
I'm not sure if they have tracfone in your area, but I've had wonderful experience with it. They have phones that do all kinds of things, but I just got a simple one. He actually could play games on it, but no texting or anything like that. And, I figured with a phone that cheap, if he lost it, it wasn't the end of the world. He didn't lose it.
He's 16 now and has a phone that came with his dad's plan, but the tracfone worked great for us.
Best wishes.