Wal-Mart is expanding its discount prescription drug program to offer a 90-day supply for $10. It's also adding several women's medications and cutting the price on more than 1,000 over-the-counter drugs.

This means the world's largest retailer is now filling prescriptions for up to 350 generic drugs for $10 for a three-month supply. Sam's Club and Neighborhood Market pharmacies are included along with Wal-Mart stores.

The additional women's medications available for $9 include drugs to treat breast cancer and hormone deficiency.

Wal-Mart also said it's lowering prices on more than 1,000 over-the-counter medications to $4 or less. It says the discount drug program has saved Americans more than a billion dollars since it was introduced in 2006.