Money mouth

A person who constantly brags about materialistic things and sees materialism as a form of self worth.

John mentions his Ferrari at every opportunity possible. He’s such a ‘money mouth.’

Put your money where your mouth is

To actually do whatever you’re talking about

Person 1: “I could totally shoot scratch on our golf course”
Person 2: “ $100 says you can’t”

Person 1: “Well I don’t wanna….”
Person 2: “Cmon put your money where your mouth is”