Wal-Mart will roll out its four-dollar generic prescription plan in 11 more states today, including Colorado.

The Arkansas-based discounter started the discount drug program in Florida in September and is stepping up efforts to expand it nationwide.

Today's launch has the company selling 30-day supplies of 331 generic drugs in 811 more pharmacies around the country.

Retailing rivals such as Target and BJ's Wholesale Clubs have launched similar programs and are working to expand those offerings.