Recently in an another game, I have made an ex doc wagon employee turned Ghoul. I figured he still has some connections with the underground and most pacifically in Organ Running. I know I've seen or heard it somewhere how much profit is in this business, is there a book or pg number I can reference?

Vice pg 144 is the biggie.

If you don't have Vice, Augmentation has some dirt on it as well, page nr. 16!

You might also want to consider giving him some connections to Asamando (detailed in the nations section of the Sixth World Almanac) if your game is going to be globe-trotting.