SwampDonkey,
I'm not sure how close you live to the US Border, your location is listed as Northern Ontario (that's a very big area!). If you are within reasonable driving distance to the Soo you may find it worthwhile to open a mailbox in the US and have items sent to you there (USPS PO Boxes cannot have courier-UPS, FedEx, DHL, etc. packages delivered there). You could then bring them into Canada and pay GST on the goods (assuming no prohibited items).
Purchasing items in the US and having them shipped to Canada increases the shipping cost greatly (usually double). If you use a commercial shipper (like UPS, FedEx, etc.) they will usually charge a minimum $25 customs brokerage fee as well as getting billed for GST and possibly duty. If the location will ship them to Canada, use the Postal Service as they do not charge customs brokerage fees.
I previously lived in Canada and I appreciate your efforts to teach the kids. Anything we can do to help the next generation is a good thing.