where can I get the cheapest iPhone case at a retail store not online?

Give it a few months. ;-)

best buy sells a slwwvecase logic iPod soft case is like a padded nylon sock; for the iPhone itself just use the krystal clear film for the multitouch screen. Each are under $15 and most of the other cases are scratching up the iPhone itself as I've boujt three so far...best bet to go 'naked' with it and sock it in your pocket.

A iphone hard plastic case will protect your iPhone should you drop it. Hard cases offer maximum protection.
iphone Skin case: Skin cases allow you to keep the slim factor of the iPhone, but protects against scratches. This type of case usually comes in a variety of colors.
Flip lid: This allows you to protect the screen of the iPhone, but easily access the interface by flipping the cover or lid.
and take it easy ,all of them priced at $2.99 .and all of them are high quality!Just take a look…...