Thanks ... just checked the Canadian folks. Only $31.45 shipping (mail) for (10) 8M parts ... just how stupid is that! Priority mail only costs $5.50 for a pound ....
Having built one-off prototypes using parts and circuit boards from a half-dozen countries, I can say that you've been spoiled by the relatively inexpensive inside-the-US shipping options.
Priority Mail is a USPS service inside the US - you can't compare it to any cross-border shipping. You should check the Priority Mail equivalent prices for things going outside the US.
Any time you cross borders, there's a significant charge for the added handling, whether UK->US or Canada->US. It's not the vendor, just international policies. The only cheap international shipping seems to be China->everywhere and Thailand->everywhere.
Shipping charges on orders from RevEd aren't bad if you stay below the magic number (don't remember the amount). Once you hit that magic number, you're into guaranteed delivery shipping, so think FedEx prices instead of Parcel Post. Sometimes it's cheaper to made multiple small orders than to go over the magic number. I've had no problems with small order shipping from RevEd.