I used to think those types of deals were good too. After a year of $12 per month TOTAL for two lines on Xfinity Mobile (Verizon network, as stated already) I laugh at such offers. The same usage even off-contract cost us nearly $80/mo. The difference is $68/mo so at 2 years to get the "deal" would cost me $1,632 extra just for service. Even I can do that math.