One thing that might be worth investigating - that same vendor sells stepper motors via aliexpress.com. In some cases, their prices are better there than their eBay prices for the same items. In other cases, their prices on aliexpress.com are laughably higher. You need to carefully examine both the item price and the shipping price before ordering (duh - but the quantity pricing including shipping can be confusing on aliexpress.com if you don't pay sufficient attention).
See
http://www.aliexpress.com/fm-store/103343 for CHANGZHOU LONGS MOTOR CO.,LTD.
I have not looked there for these specific motors, however I recently bought a set of three 290 oz. in. 6-wire motors from them for a total of $96.00 including free shipping, IIRC (including the $5 off coupon that you get when you become a registered user of aliexpress.com).
YMMV...
Update: It looks like you can buy four of those motors, not including the TB6560 controller or 24V 350W power supply or printer cable for a total of $276.03 including shipping to the United States here:
http://www.aliexpress.com/fm-store/1...outer-KIT.html
The shipping calculator for that motor combines shipping when you specify a quantity of 4, which accounts for a significant savings - whereas with some other items, it seemingly does not. I have noticed some sloppiness in the eBay listings from this company in the past (for example, the title of the referenced eBay auction states "4-axis" and shows a photo that includes 4 steppers, while the description says "3-axis". My guess is that they work off of a "boilerplate" eBay listing, and do not carefully check to ensure that each auction corresponds with the description in all details).