Where is the cheapest place to get a iPhone 5?

So where is the cheapest place to get a iPhone 5 (I live in Australia ) also what r the differences from the iPhone 4 to iPhone 5

Both walmart and radio shack are offering the best prices I have seen so far at least on 5C.
Starting Saturday, RadioShack customers purchasing the iPhone 5C in-store will receive a $50 gift card that can be used toward their $99 iPhone 5C purchase, a spokesman for the company told MarketWatch. That offer ends Nov. 2. Starting Friday, however, Wal-Mart will also cut the price of the iPhone 5c from $79-a $20 discount on Apple's price-to $45 throughout the holiday season, a Wal-Mart spokeswoman says.

Try Craigslist or Ebay

-Craigslist: Craigslist comes with face to face business. Within two weeks of emailing at least 10 people with your offer, you should be able to secure an iPhone or iPad deal.
-eBay: eBay comes with buyer protection. Smart buyers will come in and bid $10-50 for the phone even though there are no images up. If the bidding completes at $50 and an iPhone is worth $200+, the seller has to sell it unless if they want to risk negative feedback. So always watch out for listings on eBay and bid on ones you think you can win.