If the Subtotal of any single purchase is $150 or greater prior to any other possible discounts, all shipping charges will be waived. This will be reflected in the “Cart” and “Checkout” pages.
The shipping method for the Free Shipping promotion is USPS Ground.
You may upgrade the Free Shipping to USPS Priority Mail for $10.
You can compare the shipping options at https://www.usps.com/ship/mail-shipping-services.htm#quickcompare.