I just ordered a Prusa Mendel kit from NWRepRap. They were extremely friendly and very competent, and I am excited for my new RepRap to arrive. The kit price was great, and I love the completeness of the BOM. While I was at it, I purchased a 5-lb spool of black PLA. NWRepRap hsa it for a good price, and their shipping wasn’t bad (it depends on you location and the weight of your order).
I also ordered some tools to go with it: a dial caliper (because those cheap digital ones eat batteries too quickly), some end-wrenches, and a long ruler. Calibrating the printer is crucial, and I want to get it right. I also ordered some wide Kapton tape for the print bed and some silicone and wire wrap.
I am excited to assemble my open-source printer, and I will be posting the process.