How much inventory do you need for your online sales? Of course it all depends on the number of sales that you are having. But keep in mind that the minimum you should keep is at least 1 (2 of less expensive items that may sell quicker) item in stock for each one you display online. Why? Because people who shop online expect things quickly. If you already have the items packaged and waiting on a shipping label, you can ship as soon as payment is confirmed. This keeps the want-it-now customers happy and will increase repeat buyers.