Hello friends. Amazon sells a great number of its products, but many of them are not labeled as Amazon. There is an ACoS formula. You can find out more here https://sageseller.com/blog/what-is-amazon-acos-and-how-to-easily-calculate-it/ . This unique profit formula. This makes it easier for you to track all expenses and get an idea of the amounts.
I usually but small items like books and the occasional organic fruit spreads and shipping isn't too bad. But for bigger items, perhaps you can consider Amazon Prime or even do a spree to save on shipping?
I buy many things from Amazon. some has free shipping if you spend $125. usually I will try to get the free shipping. the shipping is fast too!