Deal Fisher via eBay offers the refurbished Logitech K480 Bluetooth Keyboard in Black, model no. 920-006342, for $22.99 with free shipping. (Big Deals via eBay offers it for the same.) That's a buck under the lowest total price we could find for a refurb elsewhere, although we saw one for $12 less via rebate in December. It features 81 keys and a wireless range of up to 30 feet.
A 90-day warranty applies, but it's unclear who backs it.