Sprint and MTV: Music Television last week began selling the MTV Spree card, a prepaid calling card designed by the cable network that lets users make long-distance calls or gain access to MTV's exclusive 24-hour telephone information line. The cards are sold in denominations of $5, $10 or $20 in nearly 2,000 Blockbuster Music, Musicland-Sam Goody and Spencer Gifts retail outlets nationwide. Spree, Sprint's branded prepaid calling card, also sponsors MTV's Ultimate Winter Experience, a series of adventure programs. "We're going after a young, hip and carefree consumer," said Marlene Waltz, director of Sprint's prepaid card sales and marketing. "MTV is perfect for tapping that market."