Newegg offers the refurbished HP K4000 Bluetooth Keyboard for Tablets and Smartphones, model no. E5J21AA#ABA, for $15.99. Coupon code "AFEX15D62B" cuts it to $9.99. With free shipping, that's $3 under our mention from a month ago and the lowest total price we've seen. (It's also $16 below the best price we could find for a new one today.) It features a range of up to 30 feet. Deal ends June 5.
A 90-day warranty applies, but it is unclear who backs it.