Scenario

I would like to offer free shipping to the United Kingdom and no where else. How would I achieve this through a coupon code within Magento?

Solution

Firstly you will need to create the Free shipping code under the tab Promotions>Shopping Cart Price Rules inside this option you will be able to create the free shipping coupon. Here are a couple of screenshots to show how the coupon code configuration should look to achieve free shipping:

 

Under the Conditions tab is where the specific country will be set for the free shipping coupon code. You will need this set exactly as shown in the screenshot below otherwise the coupon code will apply to all countries.

The way in which you set this is by clicking on the green plus symbol and choosing the Shipping country option and then specifying which country you would like this coupon to apply. You can have more that one option all you will need to do is state this by clicking on the green plus symbol.

Once these processes have been completed you will need to set a delivery method to show as the free option at the cart and checkout processes. If this option is not set then the free shipping will  The following screenshot shows how to achieve this in Premium Matrix: