Can I use an iPhone 3G WITHOUT puchasing the data package?

My friend is giving me his 3G iphone so he can get the newest one. I don't want to invest an extra $20-30 a month for the data package because I don't really need to use the internet or anything like that. I just need to be able to make phone calls, and text. I have AT&T. Is it possible to use the 3G iPhone without the data package? If the answer is yes, what features/functions will still work with the iPhone without the data package? Thanks.