Q: why does my iphone 5 use so much internet data when im not connected to wifi but also not doing anything on my phone?

Here's Apple's knowledge base article about conserving cellular data:

HT4146

it maybe because you have location servis on and its tracking you. i would go into your settings, it would be under privacy.

and with iphones its strongly recomended you have a min of 3GB

same problem here....i surf/download on my android for about 500 MB a month, she does nothing on her iphone 5 but is consuming about 250-300 MB a month.

There are apps on the phone that update in background. With almost a million apps in the app store it's difficult to say which ones are using data, but start with social networking and news apps. FaceBook, Twitter, LinkedIn, photo sharing apps, etc. Also Push email accounts - MS Exchange (company email), Yahoo mail, iCloud, live.com, gmail, etc.