MightyApe offers the Logitech Ultrathin Folio Case for iPad Air (Black) for $49 + $2.90 shipping. They normally sell this for $69.99 + shipping. Most retailers sell this for around $100 according to Pricespy.
Ultrathin Keyboard Folio for iPad Air (5th Generation): Built-in Bluetooth keyboard with full-size keys and iOS shortcuts for fast, fluid typing
2-sided protection: Durable, water-repellant case protects front and back of iPad
SecureLock system: Low-profile clips keep corners of iPad firmly fastened to the frame; Powerful hidden magnets keep folio securely closed when you are on the go
Dual-view stand: Folio doubles as a stand; Holds iPad upright for typing or flat for web browsing with keyboard hidden
Auto wake/sleep: Automatically wakes your iPad when you open the cover and puts it to sleep when closed