Wal-Mart has completed the final phase of its ‘Site to Store’ rollout to more than 3,300 stores across the country. The service, which Wal-Mart  launched in March, allows customers to order products online and have them shipped for free to a local Wal-Mart store.

As a result of transportation and packaging efficiencies, the company says that 1,000 gallons of gasoline are saved each week and 20,000 fewer boxes are used each month.

Since March, approximately one-third of all Walmart.com sales have been placed through the program.