play with house money

Referring to a casino, where gambling one's winnings from the casino ("the house") may feel less risky than gambling the money that one brought from outside.

play with house money (third-person singular simple present plays with house money, present participle playing with house money, simple past and past participle played with house money)

1. To be in a situation where little or no personal risk can be incurred.
2. To act as though little or no risk can be incurred.

• bet the farm