The easiest way to find out if Sprint is running promotions is to check the Promotions page at Sprint.com. TechBargains is another website to where you can look for a variety of Sprint promotion codes and coupon codes.
As of August 2015, the most current Sprint promotion is the Cut Your Bill In Half promotion. Under this plan, a current Verizon or AT&T customer brings his phone and bill into a Sprint store, signs up for a new contract with Sprint and receives a new phone or multiple phones with the promise of a monthly bill that is half of what the customer paid with his former phone company. According to Sprint, this half-priced rate lasts as long as the customer remains current on his bill and keeps the same device. Additional charges may occur due to roaming and data usage.
TechBargains is a company separate from Sprint that offers a list of Sprint promotions and coupon codes for potential customers. August 2015 Sprint promotions on this site include the Sprint Family Plan, which includes four phone lines with 10 gigabytes of data for $100 per month, the 10% off Monthly Services discount for AAA members, and the $50 per month Simply Unlimited Plan Exclusively for Apple iPhone 6.