You may see your shipping charges at any time before entering the checkout process:
Add the items you would like to purchase to your shopping cart. Click "Shopping Cart" at the upper right corner of the page.
At the bottom of the shopping cart page there is a shipping calculator. Enter your zip code, state, and desired shipping method, and click the "Apply" button.
The shipping charges will now show up in your shopping cart and will automatically update when an item is added or removed, or a new shipping method is chosen.