in pocket - Phrases/Idioms
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Having funds; also, having a particular amount of extra funds that constitute a profit. For example, Tom's in pocket this week so let him treat us all, or After a day at the races she was a hundred dollars in pocket. [Mid-1700s] Also see in one's pocket.