Procter and Gamble Company has big sales expectations for its new over-the-counter version of Prilosec, the heartburn and ulcer drug. The Cincinnati-based company is predicting up to 400 (m) million dollars in retail sales of its Prilosec O-T-C during the first year. Industry watchers welcome P-and-G's product -- along with those of two other companies which plan to sell low-cost generic competitors. Analysts say the new competitors to Prilosec could greatly reduce costs for people who have no prescription drug insurance coverage. P&G already plans to have at least 850 trucks delivering its Prilosec OTC for its U-S rollout on September. Company officials say that would be one of P-and-G's biggest product rollouts. It's the latest entry in an increasingly crowded, 12 (b) billion-dollar market for competitors of Astra-Zeneca's.