Where can I get a iPhone 5 or 5s cheap at?

I have the 4 but mines is cracked in the back and need a phone!

You can't get a expensive premium smartphone "cheap". Do look on eBay or Amazon for good deals on used phoned.

Buy a "dead" iPhone 4 from ebay then just swap the backs.

On a 2 year contract with one of the Big Four for a $50-99 5c with approved credit is about as good you will get. Best luck. Outside of that the words 'iPhone' and 'cheap' never go in the same sentence because it doesn't exist. Best luck.

Look on EBay. They have cheap ones on there but you have to bid but if you bid at the last minute then you have a higher chance of winning. Be careful for scammers though, they may sell fake ones.
Or you could just get one on contract, but I prefer a pay as you go because it find contract phones annoying.