Zones & Rates (Weight Based) - This is the default option. If enabled,
zones and rates are required. This
is the recommended option if you have multiple buy options per product.
Per Product Rates - If enabled a "Product Shipping Cost" box appears on all
add product pages for you to
enter the shipping cost for that product. For this option, countries must still be enabled, but zones and rates are ignored. This is only
recommended if you have products with a single buy option.