Give it to customers for a small one time fee (one per household?) and make your money on their cell phone usage when they’re not at home. This does many things:

1. Decreases the load on your cell towers – more customers per tower on average
2. Convenient for the customer
3. Incentive for the customer to use their cell phone more, becoming even more dependent on it
4. This would be a competitive advantage over other companies, a unique offering.

I haven’t used Sprint in quite a while and don’t really ever see a reason to, but things like this might make me think twice.