A quick google search turned up this place: Home Training Tools.
They ship to Canada, though there are certain things they will not ship across the border such as potassium permanganate. They are specifically designed to service people like you. Note the quantities of chemicals are very small. But so is the price.
Living in Mississauga maybe you can organize with a parent or an older friend to get a mail drop someplace in USA (Detroit?) just over the border and then once in a while you can drive there and pick up the stuff.
You might also check out the original FAQ on Chemistry from the old Usenet. It has a question in part 2 that addresses your problem (somewhat):
9.3 Where can I purchase chemicals?
The chemicals usually found in home chemistry sets can usually be purchased at the shop where the set was obtained, or the local hardware shop or pharmacist, provided the chemical is not subject to government or state restrictions. Many chemicals are only available to approved purchasers. If the chemical is used for a hobby, then it is very likely the FAQ for that Usenet group ( eg rec.pyrotechnics ), will contain information on suppliers. Most national chemical societies publish an annual listing of suppliers with their journals. Standard trade directories ( eg Chem Sources [2,3] and OPD Chemical Buyers Directory  ) list companies who specialise in chemicals, however few will be interested in small purchases.
Smaller specialist and boutique suppliers are usually more likely to sell small quantities of chemicals to individuals. Most larger suppliers of high purity laboratory and industrial chemicals ( eg Aldrich-Sigma , J.T.Baker  ) will only sell a limited range of chemicals to individuals , and usually do not provide any discounts for individuals - unless they have an account with the company. I'm not sure about the US, but here in NZ discounts can halve the price of most chemicals.
If you are intending to acquire a wide range of chemicals over time, an account may be a good idea, however remember that you may then be subject to inspection visits by regulators if you purchase certain chemicals. Most government and corporate organisations and laboratories also have policies of not supplying unknown individuals with *any* chemical. Some chemical suppliers are also accessible via the Internet ( refer Section 7.10 )
So, while this is not terribly helpful, it gives you some ideas. A trip to a library to look up some of those journals and directories is in order.
Good luck--and above all: be careful!!