The Jigsaw Man by Gord Rollo

Michael Fox is a homeless man living in a garbage dumpster beneath the Carver Street Bridge in Buffalo, NY. He's bitterly depressed and ready to commit suicide; anything to put an end to his miserable existence.

AN OFFER TOO GOOD TO REFUSE...
When a mysterious billionaire surgeon offers Michael two million dollars for his right arm, he thinks his luck might be about to change. Little does he know that the surgeon has other plans for him. His arm is only the beginning. Bit by bit other pieces of Michael's body are surgically removed; his natural body stripped away and then reassembled using other harvested parts from thirteen different 'donors'.

A MODERN DAY FRANKENSTEIN..
Now Fox isn't sure if he's a man or a monster, or whether or not he'd be better off dead. One thing he is sure of though, he's not checking out of this world until he finds a way to make the people responsible pay for turning him into the experimental nightmare known as... The Jigsaw Man