I order from Rainbow Ten Hobbies in Japan, they've got real good prices on Tamiya, Hasegawa, Skywave/Pitroad, basically, all of the Japanese producers. Shipping is reasonable, and it takes about 5-7 days for it to arrive here in the states.
Gouging prices on Ebay for shipping is a pet peeve of mine...I recently won a Verlinden 120mm US GI weapons (which is out of production) for $6.50...the guy was in Texas, and wanted $12.00 for shipping standard ground rate!! Needless to say, I prepaid the shipping (via UPS) and sent him a MO in a box. He probably wasn't happy about it, but it cost me $6 to mail the empty box and have it mailed back. At that point, it's a matter of principle.
The best are some of the overseas sellers...they'll sell a kit for 50% of the retail, but charge you more for shipping, only to find it cost them a fraction of that to actually ship it. There's someone on Ebay right now selling 1/16 T-34s for $58US, but $45US shipping.
J