Bananabin alerts users to a full trash directory by surrounding the bin with buzzing, animated flies that can be shooed away with the mouse. The flies appear when the data in the Trash folder surpasses a user-configured threshold.
Yes, Bananabin is currently free to use while it's in beta. The developers plan to charge a small, as-yet-undetermined one-time fee for the release version.
The purpose of the Bananabin app is to provide users with a playful reminder to empty their trash folder on their computer when the data kept in the folder passes a certain threshold. The app surrounds the trash icon with buzzing, animated flies that users can shoo away with their mouse. The app is currently free during its beta version and offers three configurable fly threshold options.