The first son went out and sold his duck for $5, went home and told
his dad what he had done. His father congratulated him and told him
to go and buy himself a beer

The second son also sold his duck for $5. His father congratulated him
and told him to go and buy himself a beer

The third son went out and saw a gorgeous blonde woman on the side of
the road. He went up to her and said I'll give you my
duck if you have sex with me.

She considered it and said "Ok".

They had sex and when they were done she said wow that was good, I'll
give you your duck back if you'll do me again.

The boy agreed. While they were having sex again, the duck got loose and
ran out into the road. They saw the duck escape and
pulled their pants on but not quickly enough to prevent the duck from
getting run over by a car.

The driver jumped out of the car and said "I'm so sorry i killed your
duck. I'll give you $40 dollars to make up for it.

When the third son finally returned home, his dad asked how much he
had made.

He said "I got a fuck for a duck, a duck for a fuck, and forty bucks
for a fucked up duck."