As one of its daily deals, THAT Daily Deal offers this Waterproof Case for iPhone and iPod touch
(pictured) for $9.99
for shipping. That's $5 under the lowest total price we could find for a similar case elsewhere, although we saw it for $8 less last summer. It's designed for use with the iPhone, but is also suitable for use with the iPod, Blackberry, and most other smartphones. Deal ends today.
Of note, THAT Daily Deal also offers a Waterproof Case for Tablets for $18.98 plus $2.99 for shipping. (Choose this option in the drop down menu in-cart.) That's the lowest total price we could find by $3. This case fits most tablets including the iPad.