I want to buy an unlocked iPhone 5c in USA, find a no contract SIM card for USA, and also be able to use it on trips to UK, possibly changing the sim card there. What model should I get and is this possible?

Hey samfromshrewsbury,

Thanks for the question. The following purchase page may have the information you are looking for:

iPhone 5c - Buy iPhone 5c in white, pink, yellow, blue, or green - Apple Store (U.S.)

http://store.apple.com/us/buy-iphone/iphone5c

If you buy a SIM-free iPhone, you will need to purchase a GSM-compatible nano-SIM card separately. In the United States, you can purchase such a SIM from AT&T or T-Mobile. When you travel internationally, you can use a nano-SIM card for iPhone 5c from a local GSM carrier. The unlocked iPhone 5c model is A1532 (GSM).

Thanks,

Matt M.

A US sourced iPhone will not work in UK on LTE (4G ) .

As long as you follow the above advice and buy from Apple and only Apple 3G will be fine