1. Medicine refining, this is more cost-effective. In the lower grades, learning 10 is enough. At this time, all kinds of 3 drugs can be trained. It doesn't matter if the quality is low. Anyway, they are all sold to teachers, and they are all about 3W (the old district will be about 2W, but the ninth turn will always be above 4W5, the scorpion will always be around 3W5 and Jin Xiangyu will always be above 4W). (Recommended formula: 2 camellia /2 clove water +2 1 medicine, which can break the cost for gold sores and make a lot of money for other medicines. )
2. Cooking, because there is no cost (ignoring vitality), so the price is low, and there is no money at all in the early stage, so you can only use it yourself. Therefore, it is suggested that learning 10 is enough and you can be your own teacher. Even if it is sold, it will only cost about 5000-8000. You start to make money slowly when you are out of the den, but when you are drunk, it is as good as the three medicines, really.
So, what you choose depends on your hobby. Anyway, 10 is enough for any early stage, and you can also go to high school in the middle and late stage (when you are almost 70).
I recommend refining medicine, because I study refining medicine.