To set the purchase price, you have three options:

This field is relevant if you haven't selected a supplier for this product yet and still want to store a purchase price, e.g. for the first time as part of a stock initialization. The price you enter in this field is also used when assigning the product to a supplier (and can of course be adjusted afterwards, see below). As soon as you put away a delivery with this product, the value in the field is overwritten with the new purchase price.

If you source the same product from multiple suppliers, you can enter the purchase price individually for each supplier. To do this, open the corresponding supplier under Products → Purchasing → Suppliers and then switch to the Product assignment tab. On the right-hand side, you'll see all products assigned to this supplier and can adjust the price by double-clicking on the corresponding field. The price for orders then depends on which supplier you order from.

Using the profiles Pickware Stock (absolute values), Pickware Stock (relative change) and Pickware Product-Supplier assignment, you also have the option to store the purchase price of a product. You can find more information about CSV import/export and the individual profiles here.