WooCommerce USPS Shipping Method Extension: WooCommerce extension for USPS Shipping is almost similar to what we have described earlier at UPS Shipping Method and Fedex Shipping method and works almost exactly similar to those extensions. Only differnece seems to be that it is using USPS API for data and hence you will be able to provide USPS shipping method preferneces and rates to your customer at checkout. Requirement includes base currency to be US Dollars for it’s currency and United States, Puerto Rico or the US Virgin Islands as the base country.