I used to buy all of my business supplies from www.detailedimage.com out of NY state however I stopped as the international shipping costs and sporadic customs charges were getting over the top. I buy in large quantities for my business and eshine offers free shipping for orders of $150 or more so it's actually cheaper for me than going south of the border.
Some things are close...at best. Plus I'm sure you get better prises that most of us would.

But many products are at opposite ends of the price range.
For example, I bought a 32 oz bottle of Meguiar's #205 Ultra Finishing Polish...
AutoGeek sale priced ran me CA$20.31 with an rate of 7%...it is now 0%.
eshine price: CA$38.49....come on, thats almost double the price.
Then my Flex XC 3401 VRG dual action polisher. For $30 less than the price of the polisher alone at eshine, I got the polisher, 3 Lake Country 6.5 CCS pads, Pinnacle XMT Series pad cleaner, Pinnacle XMT Series pad conditioner and a very nice Flex padded bag for the polisher and accessories. Or if you want to compare the polisher alone; $310 vs $375....helllooooo...the dollar is at par, eshine!
I know you can alwys find that "one item" that'll be cheaper here, but I am talking about on a whole.