How much will it cost me to buy an iphone 5 with no contract?

No contract iPhones are still locked to a wireless carrier in the US.

What you want is an unlocked iPhone and none are currently available

in the US nor has Apple announced when they will be.

Unlocked iPhones are available in Canada, parts (if not all) of the

EU, and other countries. Suggest you purchase outside of the US.

Are iPhones not available at your location?

Keep in mind that warranty and support are only valid in the country of origin.