Will this app work on my plan type?
The simple answer is Yes, the Postcode Shipping app will work on all Shopify plans.
Carrier Calculated Shipping is required to use Postcode Shipping. This feature is available by default on Shopify Advanced and Plus plans.
If your store is on a lesser plan (regular Shopify or Basic Shopify) you are still able to get it by switching to annual billing and requesting the Carrier Shipping feature from Shopify Support. This won't cost you anything extra. Follow the Pre-install setup guide to find out how.