Newegg offers the refurbished D-Link 802.11n Wireless Range Extender, model no. DAP-1320, for $14.99 with free shipping. That's tied with our mention from three weeks ago as the lowest total price we've seen in any condition. (It's currently $20 under the best price for a new one.) It delivers up to 300Mbps for whole-home coverage.
A 90-day warranty applies, but it's unclear who backs it.