inkcredibleprinting via eBay offers this 2,500mAh Battery Case for Apple iPhone 4/4S
in Black for $9.99
with free shipping
. (It's available in seven other colors for $1 more.) That's tied with our mention from a week ago and $2 less than the lowest total price we could find for a similar 2,500mAh battery case elsewhere. It includes a screen protector.