If you want to open a keyboard shop, you have to do some research about the area where are you living, to see what's average age of the people from that place, their approximate income, interests and things like this. One of my friends has a small shop running and he shared a bit of his experience with me. He is buying most of the stuff from
https://www.yorkn.com/ because they have good prices for high quality merchandise. Also the delivery is free and in this way he is saving money to be able to sell the products at a decent price and have an income at the same time.