Cashy (also called Betsy and Kassie) is a cash register and the co-owner of the Krusty Krab. It first appears n the pilot episode "Help Wanted," and has her first major appearance in "SpongeBob SquarePants vs. The Big One." It appears in most episodes that feature the Krusty Krab. Cashy is rarely mentioned by her name.
Mr. Krabs got Cashy when she was just a little calculator and raised her as if she was his own child . Like Karen Plankton, she was a calculator when she was younger.
Krabs refers to this technology as an automated money-handling system.
It could be concluded that the register is prohibited to be touched by any non-employee since no one else besides himself, Squidward, or SpongeBob has ever touched it without his worry, as revealed in the "Krusty Krab Training Video."