We have alient, Telus and Rogers here....depends where you are if Rogers is worth it. Here they only have 2 towers, so the crappy reception isn't worth the deals they have
I also saw some cheap pre paid phones at 7-11 for Fido and you get a credit voucher.
I also noticed today at London drugs you can get reconditioned cell phones starting at $40 plus tax, if thats what you want. Thats about as cheap as you will find I think.