As one of its daily deals, Amazon offers the Logitech K750 Wireless Solar Keyboard, model no. 920-002912, for $35.62 with free shipping. That's $2 under our November mention and the lowest total price we could find now by $12. This wireless keyboard is powered by light and measures only 1/3" thick.

Also available is the Logitech K750 Wireless Solar Keyboard for Mac, model no. 920-003471, for $39.99 with free shipping. That's the lowest total price we could find by $19, although we saw it for $2 less in December. Specs are as above. Both deals end today.