The Pinch-o-Matic is a machine in the Krusty Krab that was built by Mr. Krabs. It just appears in the episode: Born Again Krabs. If someone puts rubbish into it, Mr. Krabs runs into the kitchen to check how much money he got.
Pinch-o-matic: Pinch-o-matic has saved you 5.2 cents.
SpongeBob: But, Mr. Krabs, I found that under the grill.
Mr. Krabs: And tomorrow a customer will find it under his bun. (hands it to SpongeBob)
SpongeBob: But, it’s old and cold and so very full of mold.