Both j.thomas and mowmore have been really good to deal with. Mowmore impressed me with accurate UPS charges. Many internet sellers "pad" the shipping charges to make a little more money on you.
There is a company that sells a "membership" for parts on EBAY. They send you a STENS catalog and a price sheet. When you get the prices you won't believe the money you save! On orders over $200 you get free shipping. I am getting ready to place an order, I'll let you know how fast shipping is.
Just make sure of the prices. I used to order from landscapersupply, but I finally did the math and realized that, with shipping, it was costing me more than buying from my local dealer. Watch out for the "shipping and handling" charges.