The cash register cha-ching comes from mechanical tills invented in the late 19th century, where opening the drawer triggered a bell to alert shop owners to a sale. That distinctive ring and drawer slide became the universal audio shorthand for commerce in cartoons, TV shows, and films. Online, creators adopted it as a meme sound for any moment involving money, profit, or paying up. Its link to the classic ding sound effect family keeps it instantly recognizable even in very short edits.