I do find the shipping expensive, but then again, like JC1 stated, we are in Canada and it is the land of getting hosed. If I have time before a repair, I look at amazon, rock, local dealer or check some local ag stores (filters). I have ordered a bit through amazon but usually rock beats them by a few bucks when all the dust clears.
I always pay for the cheapest shipping. I like the fact that they already work in the duties and tax so that I have no surprise bill at the door. Even with their cheap shipping, I find I get the parts in 10 days or less, usually way less then the quoted delivery time.