Do You Have To Have Data Service On an Old used IPhone?

[J B]

Well I want to buy a used IPhone but I Don't want to pay for the Data service for It cant I Just put my Sim card In It and att wont Start Charging me for data will they? cuz my data service Is blocked off cocompletelyo way of getting connecting internet because wee asked them to block It off so If I Just buy and used IPhone from ebay and Just put my sim car in there I no It will work but will att catch me and then satart charging I Don'think so cuz our data service Is blocked comcompletely Just turned off blocked completely