The Barbours pleaded guilty in Northumberland County Court to the second-degree murder of Troy LaFerrara, 42, last November.
A deal allowed the Barbours to plead guilty to second-degree murder, aggravated assault, robbery and possession of an instrument of crime in exchange for a life in prison and avoiding the death penalty.
"It spares the family the agony of a trial, the long, drawn out appeals in this matter and allows for some resolution on their part," Northumberland County District Attorney Ann Targonski said.
Targonski said the plea deal will likely save the community not just the pain of enduring a drawn out trial, but lots of money as well.
"I would be purely speculating, but I could see it easily being a million dollars," Targonski said.
Miranda Barbour, 18, initially claimed she stabbed LaFerrara out of self-defense, but Elyette Barbour, 22, later made a full confession, explaining that he had been waiting in the back seat of the car, then choked LaFerrara while his wife repeatedly stabbed their victim.
Police said the Barbours met LaFerrara through Craigslist with the goal of murdering someone together. Miranda Barbour also claimed earlier this year to have killed at least 20 people around the country.
"She said she has done this before," said Francis Scarcella of the Daily Item newspaper, who interviewed Miranda Barbour in jail in February. "I said 'what's the actual number?' She said 'under 100'" and stopped counting at 22.
The couple is set to be sentenced next month.