Iphone selling and buying

I have a friend who is selling her iphone and she asked me if i wanted it but i'm really confused. If i do buy it will i have her data plan with verizon? If not how do I get started with a new one and delete hers? Do I have to buy a new sim card?

Ask your carrier for the most accurate answers.

Make sure she wipes it first (her password is needed, so she has to do it) otherwise you can never set it up as your own. Have her follow these steps http://www.justtext.com/messageboards/20140127081812.html