ka-ching - The sound a cash register makes, like it’s proud of itself f

The sound a cash register makes, like it’s proud of itself for being invented by a guy who looked like he had a bad day.

'Ka-ching!' my cash register said when I sold my first sandwich, like it was saying 'I knew you could do it.'

My brother’s cash register did 'ka-ching' when he made $100 selling candy to kids who didn’t even like candy.

The cash register at my job did 'ka-ching' every time I got a tip, like it was mocking me for being poor.