All of the resources described in this LibGuide are free to the public.
Some of them have optional subscription modes that provide you with additional features for a monthly fee, but these are not required.
Freemium is a business model by which a product or service (typically a digital offering such as software, media, games or web services) is provided free of charge, but a premium is charged for advanced features, functionality, or virtual goods.
The word "freemium" is a portmanteau combining the two aspects of the business model: "free" and "premium".
Click the "more..." link for more information about these services.