RefurbForLess via eBay offers the refurbished Microsoft Xbox One 500GB Console with Controller, model no. 5C6-00017, for $189.99 with free shipping. That's $5 under our mention from three weeks ago and the best we've seen for a refurb. (It's also $135 under the lowest price we could find for a new one today.)
A 90-day warranty applies, although it's unclear who backs it.