Can I put my old sim card in an iphone and use it without being charged for data?

Ok so I have an original 2g data plan for my iphone. Everyone else in my family has regular phones which don't use internet or data so first off does my data plan only apply to my one specific phone or the whole family?

Now i got my iphone taken away but I have an old phone with a sim card and my friend gave me one of his old iphones, would I be able to use it with my sim card? And if i do use it would i automatically get charged more for a data plan. I read on a few sites that if you shut off the data on the iphone you won't get charged, but if i do that can i still use wi-fi when i'm at home without getting charged?

http://www.idownloadblog.com/2008/10/11/using-an-iphone-without-the-data-plan/

http://osxdaily.com/2012/02/01/use-an-iphone-without-a-data-plan/

these are the sites I looked it up on and I think i'm going to do it but I don't want to get charged for data and have a monster bill come in. Does anybody know if it'll work without charging me for data but allow me to use Wi-Fi?

Added (1). Oh and also i have AT&T if that makes any difference

Your data plan only applies to you. You can put the sim card inside the iphone, then go to settings general network and turn of cellular data. You can now only use Wi-Fi, but calling and texting will work. Wi-Fi is a completely different internet source than 2g so you can't be charged for using it. And if you are, then you can always sue them for not following the contract. By the way, i never get charged and do this to since i got a new plan with no data and put the sim carad in my iphone. I never ever ever get charged for using Wi-Fi, so don't sweat it.