We were on the family plan with 4 phones (10G) of data for about $160/month.
By upgrading our phones (i.e., buying three new iPhone 5s at TARGET), we "signed" up for $40 per month data plan x three phones versus our original $15 per month data plan. After reviewing our bill with AT&T, Customer Care says they cannot do anything. An unbelievable ripoff of an extra $75/month!