Newegg offers the refurbished NetGear Powerline AV 200 Adapter, model no. XAV2001-100NAR, for $12.99 with free shipping. That's $5 under our mention from March and the lowest total price we've seen. (It's a current low for a refurb by $7.) It supports up to a 200Mbps data transfer rate.

A 30-day warranty applies, although it's unclear who backs it.