The cash register cha-ching has been shorthand for money in cartoons, adverts and games for decades, long before short soundboard clips made it easy to share. This version is a clean three second recording with no voice or music, so editors can drop it over almost anything. Online it spread as a generic money sfx for memes about payday, selling an item, winning a bet or unlocking paid loot. Its meaning is understood instantly across languages, which keeps it in constant use for finance jokes and reward moments.