The Verizon offer would be a better deal. This is because 1,000 divided by 10 is 100, but 1,200 divided by 15 is 80, meaning you get 100 texts from Verizon for each dollar spent, in ratio form 100/1, on the other hand, you get only 80 texts from Sprint for each dollar spent, again, in ratio form 80/1. 100>80. Verizon has the better deal.