Metal Supermarkets is to metal suppliers, what 7-11 is to grocery shopping. And they are up front about being about convenience not price. That said, if you can walk in, they usually have a pretty good selection of off cuts and remnants to paw through, at better than their normal prices. They will also sell you an inch off the end of a bar of 4 inch diameter brass, where the other suppliers want you to buy the whole thing ($$$$$$!).
A couple of the US mail order metal suppliers have started to ship in to Canada, with pre-paid brokerage and such all sorted out (ie: no surprise bill for another $75 from UPS or FedEx)) and may be worth dealing with. Check for adds in Home Shop Machinist magazine, if you get that. Get it, if you don't, eh!

KBC and others will sell you Starrett flat and round stock in various alloys.
If you are in any size city that has any industry, hit the phone book or web and see who sells stock. I have bought full sticks for less than the cost of what I needed out of other suppliers, by shopping around. Like ~$30 for a 12 foot stick of 7/8 12L14 round. They cut it in half for no charge too. Prices vary. A lot.Some outfits don't want to deal with small orders, some are only willing to sell on an account basis, some chase folks out with stupid cutting charges (was quoted $100 a cut at one place). Well worth the time spent in the lot with a hacksaw! Still the cheapest source I had at that time, too.
There are still a few old school scrap metal dealers around the country too.Had a decent on on the South shore outside Montreal that still gave out nudie calenders (because they knew their target audience pretty well) and had a great selection of rounds and chunks of various types of steels and other metals, some identified, others not, but cheap, by the pound.
Cheers
Trev