IntertiaPlugin is a membership benefit of Club GreenSock, so you need to sign up to get that. Draggable, however, is included in all the standard downloads and you don't need a membership to get that; Draggable can be used apart from InertiaPlugin as long as you don't need the momentum-based motion. GreenSock's standard license allows you to use GreenSock tools for free in everything except a very specific type of commercial project (if you collect a fee from multiple customers for the app/product/game/site that uses GreenSock tools) which makes it extremely accessible and business-friendly while providing a small funding mechanism to sustain ongoing support, enhancement, and innovation. The web is littered with abandoned “open source” projects, but GreenSock has a years-long track record of commitment to the platform. This unique licensing model is a key component of its sustainability. If you charge multiple customers a usage/access/license fee, please simply sign up for a “Business Green” Club GreenSock membership which comes with a special commercial license granting you permission to do so. Click here for details. Joining the club also gets you members-only bonus plugins, utilities, update notifications, and more.