The night after the fire, Lisa found out a $20 had been left in Wakefield. She rounded up her two teenage sons and hopped in the car, hoping the ride would change the family’s mood. Within an hour, one of her sons found the money outside a downtown gym.

“It was huge for us,” she said. “The mere fact of finding a $20 bill was like sunlight after a major storm. It shows you that there’s good faith. We all sat there in the car and cried.”

Since then, the family has made looking for twenties a weekly ritual. Lisa has an app on her phone that notifies her when money has been hidden. If it’s close to Somerville, the family drives together, and these days they bring along a flashlight in case the money’s been hidden in a wooded area.

They have won five times, and sometimes have let newcomers keep the money even if they have come upon the envelope first. When they win, they donate $10 of each find to charity.

Gail Shevlin of Wakefield also follows the site. Last year her sister, Sue Tracy, called her and told her about a $20 hidden under one of the plastic cows on the front lawn of the Hilltop Steak House on Route 1 in Saugus. Shevin happened to be driving in Saugus, and soon found the money. The sisters returned to the Hilltop the next day and used the bill to buy lunch.

“It’s only $20 but it felt like a bonus in life,” said Shevin.

There still are twenties out there that have yet to be found. And sometimes, Grant goes off the grid and leaves — exposed — folded-up bills in places he thinks they belong. The most recent were stuck in Fenway Park’s bullpen fence and center field wall after the last Red Sox home game of the year, when management allowed fans on the field.

Cook and Grant aren’t sure how big their enterprise will grow, but they are committed to giving away a $20 every day for the foreseeable future. They enjoy it as much as their followers.