Should I?

My mobile (cell) phone has started to play up. It's fine for the most part but it's not charging properly. I'm not under a contract so can't get it fixed without paying a hefty bill. For some time now, I have been considering going on a plan with my phone. As I don't live in the near vicinity of any of my family, I use it a lot to call home or to text my siblings.

Now that this one has started to play up, I'm considering it even more. If I go on a plan, I can get a new, free phone with it. But am I being silly with my money? Should I just bear with this phone until it dies?

I usually recharge with $30 credit. This does not always last me a month though, so I need to recharge again before the end of the month rolls around. If I were to get a new phone, I would have to go on the $49 plan and the one below that ($19) isn't enough. So this does sound like an extra $19 a month, but sometimes I spend up to $60 a month with my pre-paid... so maybe it's not too much. On the up side, on a plan I could call my sister for free and, as she still lives at home, can also use this to speak with my parents.

I don't really know what to do. Any advice out there?