Lenovo offers its Lenovo Wireless K5920 Keyboard, model no. 0C51501, for $39.99. Coupon code "USP1SP241501" drops it to $14.99. With free shipping, that's tied with our March mention as the lowest total price we've seen. (It's a current low by $17.) This 2.4GHz keyboard features a mini wireless receiver and ultra-thin design.
Note, this item will ship in 5 weeks or more.