Apple chips in the dehydrator is a favorite snack at my house, and they are SO SO Easy, if you don't have a dehydrator you can do them in the Oven like this, as well.
Core and slice apples in about 1/4 inch thick rings. Place the rings in a bowl of water with a little lemon juice and let them soak while you slice the rest of the apples. Then place the soaked rings on your dehydrator trays and sprinkle with a little cinnamon. Apple doe not take as long most things so watch them over about 8-12 hours until they become crispy.
At my house they we tend to pull them off of the dehydrator as they cook, they are that good.