Grails-Chargify-Plugin is a project mainly written in Groovy, it's free.
Grails plugin for integration with Chargify
The plugin is created using grails 1.3.4 and provide your application the simplified intermediate service to integrate the use of the web-services provided by the chargify that manages the billing for your subscriptions-based business into your application.
For More Details See Grails Chargify Plugin Docs at : http://github.com/IntelliGrape/Grails-Chargify-Plugin/wiki