If she's a light user then get her a 7-11 phone.
http://speakout7eleven.ca/
365 expiry on pay as you go and they'll roll the minutes over if you buy another voucher before the end of the term. I'm a light user and with the $20 initial credit + $100 voucher to get a half price phone I ended the year with over $60 in credit left.
I've also read a rumour come November they'll have a promotion for a free phone if you buy a $100 credit.