Chargecards.ca has the goods on credit cards in Canada. Check out the list of student-friendly credit cards for no-fee low-minimum-income no-credit-history-needed deals.

If you're an international student, though, searching for a credit
card is a frustrating experience. Under “Perfect for students!” and
“Low interest rate!” signs, you'll find “Must be a Canadian resident.”
It isn't entirely fair how the Canadian government gets to consider
you a resident for tax purposes but you don't get any of the resident
perks, but that's life.

Don't give up, though! Some banks are at least aware of the predicament of international students.
Calling up the International Student Centre yielded this quick tip:

Apply for the TD Canada Trust card at the Bay and Bloor branch (77 Bay Street, a short walk from campus). Don't forget to bring:

• passport
• study permit
• confirmation of address: rental agreement, phone bill, etc.
• proof of enrollment: status letter, etc.
• deposit (at least CAD 1000)

This still leaves me stranded because I'm not actually officially
enrolled yet, but hey, at least other people can use the tip.

As long as you use a credit card responsibly, it's a great way to
build credit history. It's a heck of a lot more convenient than
cash—in fact, a little too convenient sometimes. Take care of that
shiny new piece of plastic!