18-year-old Kerman High School student Lynn Snowden died last Saturday.
He was stabbed during a fight outside a party.
On Tuesday, friends held up signs urging cars and trucks to stop by the 98 Cent store in Kerman for a car wash.
Organizers say the money raised will help Snowden's family with funeral expenses.
"We're trying to raise as much money as we can," Anthony Martinez said. "Donations have been accepted and a lot of people have been bringing their cars and some just give us money just to help out a friend."
Detectives still have not made any arrests for Snowden's murder but interviewed dozens of people who attended last Saturday's party.
Another carwash will be held on Wednesday at the same location in Kerman.