Where to purchase iPhone 5?

Wal-Mart

AT&T Store

Apple Store

Your local electronic store

eBay

Craigslist

Apple store, Best buy, Walmart, Sams, Costco, CarToys and basicly any electronic stores..

or from any good mobile phone shops/stockist.

You can get an iphone at any at&t stores, an Apple store, or even online.
you can buy it at radio shack & at & t