A very useful tool that I've discovered recently is the Canada Post Comparison Shopper. If you're looking to buy a product online, it searches a large number of Canadian and US online stores to see who sells the product and ships to Canada. It's very useful for many reasons:
1. You get the results for all the stores on one page, so you don't have to google a bunch of different sellers to find who has the best price.
2. It gives you prices in Canadian dollars, with shipping, handling, and duty fees. No more having to make a cart to see what the actual cost is!
3. It can outdo Google! It often finds retailers who don't turn up on the first page or two of a cursory google, and undersell those who do.
4. All these sellers ship by Canada Post, which, as we all know, is far more convenient than private couriers.
I don't believe the Canada Post Comparison Shopper searches eBay, but it does sometimes have better deals than eBay. It also doesn't appear to search Overstock.com, and there may well be other common and credible retailers that it doesn't search either. But it's certainly worth taking 10 seconds to see if the Comparison Shopper can do better than your usual sources.