Hi!
I'm a Calgarian hailing from the northwest part of the city. Calgary's not too big on bonsai, unfortunately. There's the usual mallsai available from home and garden centers, but there isn't (to my knowledge) any nursery here that is dedicated to growing pre-bonsai stock.
I've also been having major problems finding turface or lava rock small enough to try for my bonsai. I am instead using a mixture of zeolite and regular potting soil for now, until I can get my hands on something better and do some repotting in the spring.
As for recommended garden centers, the three big ones are
Golden Acre,
Sunnyside and
Green Gate, though there are a few others that dot the city.
Outside of the city near Strathmore is
Eagle Lake Nurseries - I've never had a chance to go out there. Have also come across
For Trees, situated in Didsbury. Again, it's a location I've not had a chance to visit just yet.
As for supplies, again, since there is no place that really sells bonsai exclusively in Calgary, there are very few places that do sell tools suitable for bonsai.. and even then, they tend to be rusted over from being on display too long in a humid environment. I've just taken to using smaller cutters, etc... but things like cut paste and aluminium bonsai wire are pretty much unheard of here.