On April 20 at 5 p.m., a group of people will swarm into a single business in Lower Mills village and purchase items to help pump up the local business and neighborhood economy.

The “Cash Mob”— as its called— takes its inspiration from a national trend aimed at injecting new life into small businesses that have felt the crunch from the recession.

Carlos Vargas, the local insurance agent who initiated Cash Mob Dorchester on Facebook in recent days, was inspired after reading about other cash mobs in the newspaper.

“It might sound slightly ominous, but we assure you, it’s not,” Vargas explained. “It’s simply people who choose to spend their money at a specific business at a certain time - and the aim is to support locally owned businesses.”

Vargas said the online group will use social media to specify which day that group of people would “mob” that company.

“We thought that keeping things local was a great idea, especially if that store just opened up,” Vargas said. “In Dorchester, there are about 3,100 businesses and a staggering number of them are mom and pops so we wanted to keep the money local.”

For every $100 spent at a locally-owned business, $73 of that money stays local, says Vargas. If that same amount of money is spent at a non-locally-owned business, $43 stays local, so spending money within a neighborhood store “helps everybody” he said.

Vargas, who owns Vargas & Vargas Insurance on Washington Street, said the “light bulb went off” when he realized that they were already a socially conscious participant in Dorchester, which “added to what we already do.”

“Hopefully, the store owner thinks it’s a good thing and makes some money for the day,” Vargas said.

After hearing the idea from Vargas, Larry Marino, friend and “local techie,” began advertising the idea of a cash mob through social media.

Marino said they hope a group of around 15 to 20 people can all visit the store at the same time, especially one “that [they] might not have gone there that day.” They are planning another cash mob during National Small Business Week and hope to learn from this one for improvements.

“We’ll be absolutely thrilled if 10 people show up and ecstatic if even more come,” he said. “We hope to grow the group and continue to help out local businesses.”

To inform residents about the cash mob details, Marino created a Facebook page (Cash Mob Dorchester) and a newly-made Twitter page (@cmdorchester). He said that there will also be a blog created soon. The Facebook group currently has 146 members.

They have also been sending emails to clients, residents, friends, and local businesses. Vargas said he sent out 7,100 emails about the first cash mob.

Marino and Vargas both agreed that cash mobs should be a regular monthly event in the community. They hope to continue it all over Dorchester and also bring it to other parts of the city.