"anyone out there know's the title of this movie? Movie ends with man (I think but not sure Bruce Willis / Kevin Costner; gunshot wound) driving away from road side desert diner after paying off a debt owed this crime boss by his best friend / brother (again not sure) to this notorious crime boss (gambling loan shark); loan shark characteristics (Med. built, tall, ball, slim, stutters when excited); the debt is paid with blood tainted money, later on while still in the diner he surprises the crime boss and kills him along with his body guards. Person paying the debt off to the crime boss dies later from his wounds alongside the desert road while driving away from the diner. Naturally, patrons and employees are left in dismayed from all the killings and action in the diner."

Maybe Payback with Mel gibson. It's been a long time since I've seen that movie but maybe.

Is it 'Last Man Standing' starring Bruce Willis (1996)? Sounds kind of similar but not exact.