Help Scout Support Proxy
Use your Help Scout Support portal on your primary Shopify domain. Ends the need for subdomains, (i.e. support.yoursite.com). Help your customers by make them only remember one domain.
Help Scout Support Proxy is not available on the Shopify App Store at this time as Your Store Wizards must do back end configuration in order for the app to properly work.
Price is $39.99 per year.