Groupon offers a variety of Bunta Macbook Pro, Macbook Air, and Macbook Retina Frosted Cases bundled with a matching Silicone Keyboard cover for $19.99 plus $3.99 for shipping. That's $39 off list and the lowest total price we could find for any of these cases. Shop for cases for the 11" Air, 13" Air, 13" Pro, 15" Pro, and 13" Retina, and 15" Retina models.

Update: Apply coupon code "4JULY10" to cut the price further to $17.99.