dip into your pocket
dip into (one's) pocket
To spend a lot of one's money. We had to dip into our pockets after our construction budget ballooned beyond what we had planned.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
dip into your pocketor
dig into your pocket
COMMON If someone dips into their pocket or digs into their pocket, they pay for something with their own money. As a player, you must dip into your own pocket at times, for boots, training gear, and the odd hotel room. Note: You can also say that someone puts their hand in their pocket, with the same meaning. The only time you'll have to put your hand in your pocket is for the spa treatments. Note: Pocket is used in many expressions with similar meanings connected with paying for things. What this club needs is for the directors to dip their hands in their pockets. Note: To talk about paying a lot of money, expressions such as dig deep into your pocket are often used. Adrian dug deep into his own pocket and published the book himself. Note: You can just say that someone digs deep, or that they dig deeper. At Christmas, most will dig deep and spend more than last year. We are asking the richer nations to dig deeper.
Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012