Newegg offers the refurbished Netgear 802.11n Wireless Range Extender, model no. WN3000RP-100NAR, for $16.49 with free shipping. That's $3 under our May refurb mention and the lowest total price we've seen. (It's a current low for a refurb by $4.) Features include WPA2-PSK, WPS, and WEP encryption and two external antennae.
A 90-day warranty applies, although it's unclear who backs it.