If correct price isn't showing, Select New & Used or Other Sellers on Amazon. Pick new Amazon for $13.19
Amazon offers the Kensington KeyCover Hard Case Keyboard for iPad Air, model no. K97087US, for $13.19 with $8.58 shipping. That's $47 under our (Dealnews) mention from last December and the lowest total price we (DN) could find by $46. It features quick release rubber corners, automatic wake and sleep modes, and magnetic well.1
It's a neat hard keyboard case(kensington.com). I believe the difference between the regular and plus is the backlit keys.
Next cheapest for the non-backlit version is $96 via Staticice(staticice.co.nz).
Even generic keyboards without a case start at $41. StaticIce(staticice.co.nz)
Cheapest price ever according to Camelx3(camelcamelcamel.com)