Sprint has announced (via 9to5Mac) that it will be offering $100 off on both the iPhone 5s and iPhone 5c to new customers who port their number to the carrier, dropping the price of the 16GB iPhone 5c to $0 and the price of the 16GB iPhone 5s to $99 with a two-year contract. The move comes shortly after Sprint announced its "One Up" frequent device upgrade program, which allows customers to upgrade their phones and tablets at regular intervals. It also comes four days after T-Mobile
