I have to agree that for online purchases, Dick Blick is the most reliable and least expensive. I have ordered from other places and either got something other than what I ordered, or did not receive the purchased item at all. Dick Blick has gotten it right every time.
I am fortunate that I live close to an art supply place that has an excellent price for canvases and many other art supplies, but when it comes to hard-to-find specialty items, I have to order it online.
Since Dickblick is an American supplier of arts materials the international shipping maybe a tad too expensive, I've found amazon uk to be great for arts materials and pencils etc, but each to their own!!