Shipping costs are the killer in online ordering of art supplies, especially if you are ordering small amounts.
As I live on an island and can't get the range of supplies that I need, I often use mailorder or buy in stores when I travel. But when I do mailorder, I make sure I spend enough money to make shipping realistic in proportion to what I am buying. I sometimes share shipping costs with a friend who orders at the same time.
I order from Canadian supplies and American, but with the Canadian dollar slipping in value against the American at the moment, cost savings are that great right now. So I pretty much stay with Canadian online stores and some local supplies when I need them. If there are specialist items that I can't get here, then I bite the bullet and buy in the USA, but then I get into duty and brokerage fees and currency exchange differences.
My advice to all, is shop around. See who's having sales, note the shipping costs which are usually based on how much your order comes to and often the weight of it. If you have to pay over the top for shipping, its often not worth it unless its something you really really need.
As for quality of supplies, I have to agree. You really do get what you pay for and quality materials will make life a lot easier for both beginners and professional artists. To fight with poor quality materials often frustrates people who believe they can't work with a specific medium, when in fact, its the quality of the pencil or paint or paper that's at fault. So buy the best you can afford. Even if its one tube of paint at a time or one pencil at a time. ANd remember, holidays are coming

Circulate your wish lists now!