Bearing down on the start of the project

I took the first step toward building the CNC today (well, if you don't count the nearly $50 I've already spent on books and plans): I picked up a package of skateboard bearings at the local West 49 store. These Destructo Sendai bearings look pretty nice, ABEC-7 rated, but what do I know about skateboarding?

They were kind of expensive at $20 for the set of 8. I'm going to need at least 30 of these things. Going on the assumption that I don't need to have super nice bearings, I've ordered a bunch of bearings from vxb.com. They likely won't come in such nice packaging, but they're half the price.