That was 4 months ago, while Sprint was running their promotion. Here is my breakdown of what things cost:
Verizon bill: I was paying $170 per month for my family plan. 2 GB total data between 3 phones (yes we have very strict wifi discipline)
I switched to Sprint, they paid for my Verizon early termination fees.
New Sprint bill: $111 per month for my family plan, 4 GB. I don't know if that 4GB data is standard. The guy at the Sprint store looked at my bill, said oh you're getting 2GB... we'll double that to 4 GB free. I'm like, sure.
So I'm saving almost $60 a month with Sprint as opposed to Verizon. Now, with this new Verizon promotion, they will pay you $350 (plus the early termination fee). But with Verizon's ripoff monthly rates, it wouldn't take long for Sprint's lower rate to overtake the $350.