New Base

I'm currently working on another, improved base for Chives. The base will consist of two motors, two casters, and an 18" by 18" aluminum square about 1/2 inch thick. I'm still researching motors, so if anybody knows of any strong,cheap ones please email me. My choices rite now are 2 NPC gearmotor kits ($160 from Robot Marketplace, total of $320 for both wheels), or 2 Drive Modules( $120 from Trossen Robotics, total of $240 for both wheels), or 2 AME motors(total of $100 from Robot Marketplace) and 2 wheels(total of $20 from Robot Marketplace) as well as mounting hardware(total of $20). Here are the totals:
NPC Gearmotor = $320 *Most powerful with bigger wheels for more clearance
Drive Modules= $240 *Less Powerful with only about half an inch for clearance
AME Motors and Wheels = $140 *Cheapest, medium power but have to assemble and all parts aren't designated for each other

The base I can get for around 20 bucks from any sheet metal place. I have casters at home. If I had sponsors I would be able to get the best parts and have the perfect robot. So I'll have to make it perfect using brains instead of money and I'll measure seven times and cut once.

[I ended up picking wheelchair motors from eBay]