make (some amount of money) in (something)
To earn some amount of money from a particular career, pursuit, or undertaking. The actual amount is typically left in vague terms. I heard he made a fortune in buying up bad debt from failing businesses. With all your years of experience, I bet you could make a lot in consultancy work.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
make something in something
to make money in a particular enterprise. She made a lot of money in real estate. I hope to make some money in the stock market.
See also: make
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.