The online flight booking tool is testing out a price guarantee program that will pay customers money if the price of a flight goes down after it is booked through the service.

In a company blog post, Google’s vice president of travel products Richard Holden said, “We’ve all thought to ourselves: Should I book now in case the price goes up tomorrow? Or should I wait in case there’s a better deal next week?”

Currently, Google Flights allows users to see whether current fare prices are low, typical, or high compared to historical averages.

Now, Google Flights is taking things up a notch by monitoring a customer’s ticket price until the day of departure. If the airfare goes down between the time of flight purchase and departure, Google will send back the fare difference via Google Pay.

“Now you can book with the confidence that you’re not missing out on a great deal,” Holden said in the blog post.

This feature is currently being piloted on flights departing from the United States.