Toy vending machines provide your parks with permanent boosters and upgrades. You will be able to earn special figurines that will increase specific features in your game. Some of them will appear in your theme park! Others are passive multipliers. 
If you tap on the star icon (lower-right corner of your playing screen), you will see your collection of unlocked figures, their current level and the fragments remaining to level up.
You could get toy vending machines with in-game tokens.