If you're really stuck for cash, the Hi-Banff Alpine Centre from what i hear is a good hostle. Prices go for about $25 a night.
Here's a photo.
http://www.realadventures.com/listings/1023706.htm
And a bookings site.
http://www.hostelworld.com/hosteldetails.php/HIBanffAlpineCentre-Banff-1569
If you guys have a bit more cash but don't want to pay $500 a night, check out the Banff Park Lodge, reasonable rates for a pretty good hotel.
Hotel site
http://www.banffparklodge.com/
Their breakfast buffet is pretty good, but can be on the expensive side. Just across the street however, there's a great place for breakfast, Melisa's i think it's called... and St. James' Gate (Irish Pub by the movie theatre) is good for lunch/dinner; although not really a place to party in, just to have a few beers by the fire.