In the play's Requiem, Linda pauses a moment at her husband's grave to have a moment alone. She sadly tells him
"I made the last payment on the house today.Today, dear. And there'll be nobody home."
The irony in the statement is that Willy Loman killed himself because he thought he was doing his family a favor. After years of working at a job he disliked trying to make enough money to support his family, his work has finally paid off. They can relax and enjoy the house without having to worry about making the monthly mortgage payments. However, sadly, Willy act of suicide means that the house is paid for, but he won't be there to enjoy it. The boys are gone and Linda is left alone. The family is "free" of the debt that has plagued them, but Willy will not be with them.
Linda's last statement to her Willy's grave also shows irony.
"Why did you do it? I search and search and I search, and I can't understand it, Willy."
Throughout the play she was the champion for Willy. She supported and stood up for him, but in the end, it becomes evident that she didn't know him any better than the rest of the family.