Hi, so I'm asking for my sister who is a middle school student. Her project is to create something like a merry go around model. The horse of the model would need to go up and down (vertical motion), so we will need to have a motor for that. What is the cheapest one you'd recommend? The whole model is around 30cm in diameter with six horses (say like with the size of around 10cm height and width) that move up and down on it. Thank you for any input.