The cha-ching comes from early mechanical cash registers, whose bell rang each time a sale was rung up to signal an honest transaction to everyone in the shop. That Pavlovian link between the bell and money stuck, and cartoon sound designers adopted it as shorthand for profit, greed or success. Online it became a staple reaction effect in memes, prank videos and TikTok edits, where a single ding can sell a joke about wealth. Its brevity keeps it endlessly reusable across languages, which is why this Thai-titled upload still lands instantly.