Apple Inc needs a cheaper iPhone to keep pace with low-cost rivals, analysts said, after the companys smartphone sales fell short of lofty expectations in the holiday shopping season. Shares of the worlds most valuable technology company opened down 8 percent on Tuesday, a day after Apples weak revenue forecast for the current quarter renewed fears about Chinese smartphone demand and a tepid global market. At least 14 brokerages lowered their price targets on Apple, reflecting concerns that it was becoming harder to sell high-end phones as markets get saturated. Apple shares fell to $502.47 in early trading.