MINNEAPOLIS - Effective immediately, Target has expanded its $4 generic prescription drug program to all of its pharmacies, the retailer said this week. Target operates 1,494 stores in 47 states, although not all stores have pharmacies, the company said. Last week, Wal-Mart Stores, Bentonville, Ark., expanded its $4 generic plan to 11 more states, making its program in 3,009 pharmacies in 38 states. Wal-Mart plans to expand to all 50 states by January.