I've used Calypso at the corner of Bruce B. Downes and Amberly; I picked up a full set of gear from them and was really happy with the service, the employee attitudes, and the prices.
I don't know if I could call them "cheap", but they are definitely on par with everyone else. They also offer a rent-to-own program so if you rent a BCD, for example, 25 times you then own it.
When I was there they were also willing to work with me to help me get the gear that I needed. If you're in the area give them a try.