Money for the kids, lunches out, a short vacation: The bills stack up, and debt becomes a nagging part of existence.

Juanita Ann Waller, 54, took personal finance to heart because of her own economic struggles, becoming a forceful advocate for friends and even strangers on a topic that is often difficult for people to talk about.

Waller, of Lanham, was described as a behind-the-scenes pillar at First Baptist Church of Glenarden, which boasts more than 11,000 members. Church members said she was someone whose impact was deep.

On Friday morning, Waller and a sister-in-law, Shyrel Scott-Waller, 53, of Chester, Pa., were killed in a car accident off Interstate 66 in Fairfax County.

Juanita’s brother, Clarence R. Waller, was driving, and fatigue appeared to be a factor in the crash, according to Virginia State Police.

The three were going to a funeral for Scott-Waller’s father in Virginia, said Juanita Waller’s sister, Yolanda. Juanita Waller was the oldest of five and the family’s “glue,” Yolanda said.

“We’re just waiting for her to come in the door . . . come in and fix everything,” Yolanda said, sobbing during a telephone interview.

She said her sister was always dropping mementos in the mail to show her love. Her favorite, she said, is a figurine she looks at every morning that reads, “Ain’t Nothing Like a Sister.”

Waller, also a church staff member, was heavily involved with the Prosperity Partners ministry at the Glenarden church. The ministry is led by Washington Post columnist Michelle Singletary, who remembered meeting Waller at a workshop in 2002. She was distraught, thousands of dollars in debt after a divorce.

Waller began attending personal-finance sessions regularly, listening intently with a notebook in hand and following Singletary’s advice.

Soon, Waller cut her expenses, budgeted and eventually became debt-free. The liberating experience had her sharing it with all who wanted to listen.

“She was able to punch through people’s reluctance to talk about their financial issues,” Singletary said.

Stefanie May and her husband, Jimi, both 47, credit Waller with helping them cope with mounting debt that was attributable in part to medical expenses and college costs for their five children. May, who also works at the Glenarden church, said Waller constantly checked in on her and her progress.

One day, May mentioned that she had bought her lunch.

“ ‘Bring your lunch. Stop playing!’ ” Waller told her.

“You’re getting called on the carpet, but it’s a good thing,” May said.

May said she and her husband are in a better place now. They even saved and budgeted for an eight-day cruise, with one minor difference. They told their three oldest children that they had to pay their own way if they wanted to go on the trip.

“She wasn’t looking to be recognized or honored” May said of Waller. “She did it because she was a servant.”