Shipping and tax settings decide what your website charges at checkout beyond the book price. Both live under Settings › Commerce — the Shipping and Taxes cards.
Shipping methods and rates
Shipping Methods defines what the customer can choose (Media Mail, Priority, International Air, and so on) and what each costs: flat per-order, per-item, or weight-based rates. Shipping Zones group destination countries so a method can price differently by region. A few per-item levers interact with this: an item's weight feeds weight-based rates, a per-item handling fee adds to any method, and Ship Exempt makes an item ship free (see Editing item fields).
Sales tax
State Sales Tax sets the rates you collect by state or region. Items flagged Tax Exempt are skipped, and customers you mark tax-exempt (resellers with a certificate, for example) are never charged tax. Whether tax also applies to shipping, handling, insurance, and gift wrap is controlled by the tax toggles on the Website Settings page.