I'm in Alberta too, so I will add my two-cents about temp agencies that may be a little more locally specific. (We use one at the company I work at, and I had a friend who worked for them - like for the agency itself, not as a temp).
The pay isn't fantastic, BUT the agencies charge the businesses a great deal more than it would cost for us to hire someone of the same skill level. The reason we do it, is because the nature of our work is that occasionally we need twice the number of people we normally have, and it's easier to use temps than try to hire temporary workers ourselves. Not cheaper. Easier. Granted, this is for manual labour positions, not admin. I would suspect that you are largely going to get positions where, say, the receptionist is out sick and they need someone to answer the phones, etc. In general, people are not using temp agencies to fill long term positions.
Staffing agencies are a bit different - the employers pay a fee to have someone else find them an employee, but then you are employed by your employers, not by the agency. Did that make sense?
Many temp agencies have a problem finding decent workers. They largely attract people who are otherwise unemployable, due to substance abuse issue, unreliability, attitude, etc. If you are clean, professionally dressed, have some skills to bring to the table, and generally not an asshole, you'll probably get bumped up to some of the more choice positions quickly.
Regarding the "hiring freeze". If you find yourself in that position, it's pretty easy to get a job as temporary Christmas staff in retail. No, the pay isn't going to be great, but especially if you work at a place where you can buy most of your presents at a discount, it might work out in your favour. And would at least be some cash.