FatWheelScoot

The "Free to install, $0.1 per monthly tracked order" plan above only applies to over 10,000 orders a month - this isn't written on the Shopify app page, only on their website. I spent half an hour setting the integrations up before realising this; it would have saved me wasting the time if it was clearer. Giving them five stars though as it's not really about the product.