Your PayPal account can be set to automatically calculate and charge shipping and/or sales tax.
To view or modify your sales tax and shipping charges:
1. log in to your PayPal account at https://www.paypal.com
2. go to the “My Account” tab
3. click the “Profile” subtab
4. in the Selling Preferences column, click either “Sales Tax” or “Set up Shipping Calculations”
5. follow the instructions that come up
6. be sure to use “Total item quantity” or “Total order amount” as the shipping rate, rather than “Total order weight”