If you're annoyed by a vending machine gobbling up your cash or you're plotting against our potential robot rulers, humanity has a few cunning methods at its disposal.
Steps

Apply double-sided tape to the coin. Use sturdy double-sided tape to affix the coin to the mechanism. If the adhesive is robust, the coin will remain in place instead of falling or getting dislodged, allowing you to use it multiple times for acquiring candy.

Attempt to jiggle the knob back and forth. This method is effective only on poorly made machines or those with assembly flaws. Insert your coin into the slot and slowly rotate the knob. Listen for the machine's mechanism to release a candy piece with a clicking sound, then revert the knob to its original position. If the machine's components are misaligned, your coin will stay put, enabling you to repeat the process.

Utilize a flathead screwdriver. Opt for the smallest one available, or a similarly slender, sturdy object like a file or a large paper clip. Insert the tool into the top part of the slot, where coins typically land when the knob is turned. Explore the area for a small plastic latch and push it upward. This action should enable you to turn the knob without inserting a coin.

Master the art of hacking claw machines. If your candy vending machine features a claw mechanism for grabbing candy, you usually have multiple attempts per coin until you secure an item. By catching the item before it reaches the bottom of the dispenser, the machine won't register it, granting you the maximum number of attempts before requiring another coin.
Helpful Tips
-
If you enjoy the thrill of outsmarting vending machines, consider purchasing a miniature version for home use and experimenting with hacking techniques. Unlike store candy machines, these are managed by individuals who invest in stocking and maintenance.
Important Warnings
- Many candy vending machines in public areas are equipped with surveillance cameras.