Amazon Prime customers are now getting food delivered in two hours -- and it's free, but only available in four cities.

Customers in neighborhoods in Austin, where Whole Foods is based, Cincinnati, Dallas and Virginia Beach can take advantage of the service. Amazon plans to expand it across the country later this year. No word on when the Seattle area might see it.

Bestselling items including fresh produce, mean and seafood, everyday staples and even select alcohol can be delivered. If two-hours isn't fast enough, customers can pay $7.99 on orders of $35 or more and get it in an hour.

"Together, we have already lowered prices on many items and this offering makes Prime customers' lives even easier," said John Mackey, CEO of Whole Foods.

People in the selected cities can use or use the prime now phone app to see if the service is available in their area.

Amazon purchased Whole Foods just six months ago for S13.7 billion. It's estimated 90 million people are Amazon Prime members giving the new service a potentially huge market.