Eagle Lake *might* have peat. They drop off a monster bag (about 4'x4'x4') at your house for about $150. The phone number I have is 403-235-8873, you could give 'em a call.
Not peat, but there's a mushroom farm just north of Airdrie that has a $5 all you can load manure sale (or something). Literally, a 1/2 ton truck of #### for around $5. A friend of mine used bags and loaded them in their van. Might even be worth it to rent a truck...
I can't remember what day, though. I *think* may long weekend.
EDIT: Ah, it's Mother's day, and the farm is Money's Mushroooms, and it's actually free.
Here's a link. Also, I'm thinking it's free on Mother's day, and $5 every other day. You could give them a call too, if you're interested.