GeekDeal via eBay offers the refurbished 2-lb. Apple MacBook Intel Core M 1.1GHz 12" Laptop in Silver, model no. MF855LL/A, for $749.99 with free shipping. That's $179 under our mention of a refurb from April, $130 less than a new unit today, and the lowest total price we've seen for this model. It features an Intel Core M-5Y31 1.1GHz Broadwell dual-core processor, 12" 2304x1440 Retina display, 8GB RAM, 256GB SSD, 802.11ac wireless, USB-C port, and Mac OS X 10.10 Yosemite.
A 1-year warranty applies, although it's unclear who supports it.