In stage magic, the "Miser's Dream" is a routine in which the magician repeatedly produces coins, seemingly from out of thin air and various other places (behind someone's ear, inside someone's mouth, etc.) and places them in some sort of container, typically a metal bucket. As he adds "coins" to the bucket, they make a clinking noise against the bottom of the bucket, and by the end of the act shaking the bucket makes a sound as if there are many coins inside.
This routine is usually credited as having been invented by American magician Thomas Nelson Downs (aka the "King of Koins"), ca. 1895. There are many ways to accomplish this effect and there are many variations on the routine. A classic way to achieve the effect is to hold several coins in the hand that is holding the bucket, pressed firmly against the side of the bucket, and then repeatedly palm and produce a single coin while only pretending to drop it in the bucket. Each time, the magician secretly releases one of the coins held against the side of the bucket to produce the clinking sound.
Magician Teller of the comedy/magic duo Penn & Teller frequently performs a variation of this routine in which he produces numerous coins by reaching into a fish tank and other places all over the stage. At the end of the routine, he dumps the coins into the fish tank and the coins transform into goldfish.