Put your hand in your pocket
Definition 1 of 2
Pro Tip 1/3Generosity Implication
The phrase often implies a generous act of giving, particularly when help is needed. 
During the fundraiser, everyone was expected to put their hand in their pocket.
Pro Tip 2/3Informal
This is an informal idiomatic expression, used more commonly in casual conversation. 
If we all put our hand in our pocket, we can get the community center painted in no time.
Pro Tip 3/3Charitable Context
It's commonly used when referring to charitable donations or informal fundraising. 
The charity asked locals to put their hand in their pocket for the homeless shelter.