Yapper Wireless via eBay offers the OtterBox Authentic Defender Series Case for iPad Mini 4 for $19.99 with free shipping. That's the lowest price we could find by $22. It features dust, drop, and scratch protection.

Also available is the OtterBox Authentic Symmetry Series Case for Microsoft Surface Pro 3 for $29.99 with free shipping. That's the lowest price we could find by $19. It features 360° protection and drop protection.