My motorola broke a couple months ago and I haven't had time to get it repaired.

Before my motorola, my mother let me have her old LG 1500 since she didn't need it anymore.

I've tried placing my SIM card into the old phone but I don't know how to unlock it.

Would the Fido store unlock the old phone for me and still let me use my SIM card?

P.S. I don't really have any kind of plan. I use prepaid cards.