Can i buy an iphone 4s without making a plan?

Like switching colour like i have a white one and i wanted to get a black one so yah could i buy one off the Apple store? Like just the phone?

You could, but it's very expensive.

You can buy it on amazon i think

No you have to sell your current one and buy a new one

No. You can try to trade it in, but once you buy a new one from Apple you are bound by another 2-year contract & can't upgrade your phone without paying full price.

Yes, you can buy a 4S here -

http://www.amazon.com/...lias%3Daps

Yes I guess you can buy unlocked verion from foreign, like HK somewhere