As of April 2015, Sprint offers discounts on phones for new customers who agree to two-year contracts. In addition, customers can choose installment plans that require monthly payments over a two-year time frame; these plans typically don't offer discounts.
In the United States, phone contracts, which are common among major carriers, often offer significant discounts for phones. Sprint, for example, sells both the Samsung Galaxy S6 and the iPhone 6 for $199.99 to new customers who sign two-year contracts; this is well below the regular retail prices for these phones. However, customers willing to pay for their phones outright can opt for prepaid plans, which generally offer lower monthly payments and don't require contracts.