In operating a vehicle, gasoline, parking fees and tolls are considered out-of-pocket expenses for the trip. Insurance, oil changes, and interest are not, because the outlay of cash covers expenses accrued over a longer period of time.
Organizations often reimburse out-of-pocket expenses incurred on their behalf, especially expenses incurred by employees on their employers' behalf. Out-of-pocket expenses for such things as charity, medical bills, and education may be deductions on federal income taxes, according to IRS regulations.
To be out of pocket is to have expended personal resources, often unexpectedly or unfairly, at the end of some enterprise.
Since at least 1970, the phrase out of pocket has been occasionally used as a synonym for out of contact.