not free. If you set up a stall to sell snacks in Shanghai, you have to pay a booth fee. If there is no booth fee, everyone will do it, which is not free. But it also depends on what snacks you make. If you bake sweet potatoes or sausage, you don't need a booth fee, but you don't have a fixed position. If you want to have a fixed position every day, you must pay a booth fee. After all, there are still quite a lot of people who set up stalls, right?