|FAQ - Cart Help Buttons - Cart Settings - 6. Shipping Options - Approved Shipping Methods
One thing that effects the cost of shipping is whether the order is being shipped to a residential or a business address. Shipments to residential addresses will cost more.
With this setting you can set the cart to specify residential or business address shipments, or you can set it to allow your customers to choose.
This is a "Global Package Setting". This means that it effects UPS, USPS, and FedEx.