(diminutive of poche, a pouch).
To put one's hand in one's pocket.
To give money (generally to some charity). Put your pride in
Lay your pride aside for the nonce.
To be in pocket. To be a gainer by some transaction. To be out of
pocket. To be a loser by some transaction.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894