Hi .. after you choose to checkout, the next page that paypal takes you to is a log in page. However, on this page, at the top right you can calculate shipping, by your postal code, as well as your country, outside US, etc., I am not sure what your shipping discounts might be, or I would try it for you, but you are able to check this way .. all done before the buyer actually logs into their paypal account. So yes, you can check this out ..
OR you could sign up for paypal sandbox
https://developer.paypal.com/ Use the Sandbox Test Environment to create and manage test accounts and their associated email and API credentials.