Buy Price: You can add Buy price of the product and this price will be used when we are using the same product in Purchase Order.
Sales Price: You can add sale price for the product and this price will be used when you will select this product in Invoices, Estimates and in Credit Notes.
Unit Type: You can also add Unit Type for the particular Product. A default will be used as Quantity.
Default Quantity: You can also add default quantity.
Taxable: You can make the product as taxable and non-taxable.
Default Tax: You can set default taxes for a particular product. So when you use the same product in Invoice/ Estimates/ P.O. and Credit Note then for that item line, a tax will be set according to selected product.