What is the smallest, cheapest, easiest to take care of and most affectionate pet?

A rock. It never grows,. It doesn’t eat or drink. You can cuddle it as long as the like and it won’t ever get mad. You can pay it no attention at all and it won’t ever get mad. It doesn’t need walks. It doesn’t need a comfy sleeping spot. You can carry it all day in your pocket. It’ll defend you if you need.