The average two-car household is saving about $50 a month on gasoline, according to Bankrate.com. So where is that extra money going? Not as much is flowing into malls and restaurants as you might think.

“Consumers are very quick to pull back on spending when gas prices rise, but very slow to ramp up spending when they fall,” says Greg McBride, chief financial analyst with Bankrate.

At an Oceanic gas station in Baltimore, Maryland, cab driver Waylen Hawkes estimates he’s pocketing an extra $1,000 a month, thanks to lower prices. He’s saving it, he says, “because it’s not going to stay this way.”

“I do worry about them going back up,” says Margurite Copper, a human resource manager with a security company. “I wish that I could take some gas and just store it somewhere in my house, but it would be unethical.”

Still, Copper was on her way to the mall after filling up, where she planned to spend a little extra on Christmas presents.