(CNN) Praynksters is known for pulling off random acts of kindness for people going through tough times.

This time it surprised a 30-year-old mother in Nampa, Idaho.

In October, Amanda Kofoed found a lump under her arm. A friend urged her to get it checked.

The diagnosis was dire: Stage 3 Hodgkin's lymphoma.

Kofoed's doctor wanted to start treatment right away, but with no insurance, Kofoed didn't think she could afford it.

"I asked if they could delay my treatment until January," she told the Idaho Statesman.

A family friend, Jessie Horney, set up a GoFundMe account soon after to help raise money for medical expenses.

That's when Praynksters stepped in. One of the co-founders of the group, Jesse Fadel, is a childhood friend of Kofoed's husband, Clint.

"When we first got the news, we called all of our friends and family. They told us 'don't worry about the insurance,'" Amanda Kofoed said.

The Praynksters crew invited Kofoed and her husband to a coffee shop to make a "thank you" video for people who had donated through GoFundMe. But the most dramatic generosity was only about to begin.

As the camera rolled, almost 200 Praynksters volunteers flooded the coffee shop holding $100 bills. Each volunteer laid the money on the Kofoed's table.

"So many old friends and so many new friends -- there were people I hadn't seen in over 10 years. " Kofoed said.

The flash mob brought in more than $13,000.

"I was overwhelmed with how much I was loved and how hopeful it felt," Kofoed said.

"We are not doing this alone. We are surrounded by so many people that love us. We don't have to do this ourselves."

Kofoed, who is also a mom to four children -- ages 7, 6, 4 and 3, plans to return to school to finish her elementary school teaching degree next fall.

She was about halfway through the semester when she found out about her cancer.

"I think the main thing my husband and I want to communicate is how blessed we are, and we receive their love.

"We really see this as how God is loving us and how we can share love with one another. We didn't expect what we received."