Capsule Machine
A capsule machine could be your simplest and quickest way to break into vending machine sales. You can stock a wide variety of items in this style of machine. It is the capsuled toys that change, not the machine or the capsules.
Buy Capsules in Bulk
Since capsule machines and capsules are the staples, you should buy a good quantity of these standard items. It is the contents of the capsules that you can vary whenever you get a good deal on a certain item. If you sell stickers one month and bulk candy the next - it's okay because a capsule machine can dispense them all.
A capsule machine is especially designed to prevent malfunctioning. Clogging and tangles can all be avoided with sleek capsules that tumble upon each other without damaging any of the contents. If you don't want to risk the possibility of machine damage, a capsule machine is a smart choice.
Most vending machines these days are a version of the capsule machine. Bulk candy and gumball machines are the major exception. It may prove to be most profitable for you to own both capsule machine models and gumball machines - to maximize public appeal.