All4Cellular offers the Incipio EDGE Slider Case for Apple iPhone 4 or 4S in Purple (pictured) for $2.95 plus $2 for shipping. That's the lowest total price we could find in any color (outside of the price below) by $3, although we saw it for a buck less last month. This polycarbonate case features a 2-piece sliding shell and is dent-, scratch-, and impact-resistant.

A close price: JustDeals offers it in Purple or Blue for 77 cents plus $5 for shipping. (It's the third deal on the right.) This deal ends August 10 at 3:16 am ET.