Meritline offers the refurbished Logitech K750 Wireless Solar Keyboard for PC in Black, model no. 920-002912, for $31.99. Coupon code "MLCKA07UNL1" cuts it to $25.99. With free shipping, that's a buck under our April mention and the lowest total price we could find for a refurb by $3. This wireless keyboard is powered by light and measures only 1/3" thick. Note that this is not the Mac-compatible version. Coupon expires after 100 uses.
A 90-day warranty applies, but it's unclear who backs it.