Charlene Walker, 36, suffered a single stab wound at the Darlington home of Julie Gowling in December.
The 44-year-old tried to cover up the killing and dispose of the weapon, a kitchen knife, by burying it in a garden, Teesside Crown Court heard.
Judge Mrs Justice Jefford told the mother-of-four she must serve a minimum of 14 years in prison.
The court heard Gowling, who had denied murder, got into a heated argument with Ms Walker - a known drug user - over the missing cash on 6 December.
It ended when Gowling lost her temper and stabbed Ms Walker in the chest. She then fled the house and tried to dispose of the knife.
The court was told Ms Walker died as a result of massive blood loss.
After the hearing, Det Supt Dave Ashton, of Durham Police, said: "Our condolences go to the family of Charlie Walker who, since her death have shown nothing but dignity and courage.
"Ms Walker had a difficult life in many ways but the extreme act of violence which ended her life was not justified during an argument over a relatively trivial matter."
A woman who stabbed her lodger during a row over a missing £21 has been jailed for her murder.