Better Shipping requires the real-time carrier shipping feature in order to work. This is available on the Shopify Unlimited Plan. However, you can still add the real-time carrier shipping feature to a Basic plan (or any other plan), without needing to fully upgrade to the Unlimited plan. To get this feature added to your current plan, please email Shopify directly (https://www.shopify.com/contact) and let them know that you want to add the real-time carrier shipping feature in order to use Better Shipping. They will be pleased to add the feature to your store for a small fee.