Click on what you want to save. You do not need to change your account or your phone number. Your group is just negotiating better prices and terms for you.
Just select the amount you want to save. On your cell bill. On your Cable/TV/home telephone service. On your electric bill.
By the way, this is where you pay. The fee for joining a purchasing group is usually less than the amount you will save in the first month. We will need your credit card to join a group. If your group is not successful at negotiating the savings you want, you get your money back. All of it..