Dynamic Retrieval Rates for Shipping
Estimating shipping rates can be a long and intimidating process as you attempt to make sure every shipping possibility is covered. By far the best thing to do in my opinion is to call official shipping rates from the actual companies themselves. Magento has this feature built in, so why not use it if it’s there?
Flat rates, and even worse, table rates leave you open to the fluctuations in actual rates of shipping as they changed based on inflation and other economic movements. It’s not something you want to be caught out on. In addition to the static options like flat or table rates, Magento also offers dynamic retrieval of rates from various products, such as UPS, USPS, FedEx, DHL and more.

There’s a special extension that allows seamless integration of the Royal Mail module that does the same thing. It’s free to install so you might aswell give it a go. If you want to add a little extra for handling and packaging you are also free to do so – just add it into the backend and it will be integrated. It doesn’t appear in the site frontend either.
