money machine
/ˈmʌnɪ məˌʃiːn/noun
1The prevailing financial system; financial institutions collectively.
2A person who or thing which makes a lot of money or has no purpose other than making money; a lucrative business, product, etc.
3A machine which converts, takes, or dispenses money; specifically an automatic teller machine, a cash dispenser.
Origin
Early 19th century; earliest use found in Alexander Hamilton (bap. 1739, d. 1802), physician and obstetrician. From money + machine.