Digital Market is like many other paid downloads manager component but what makes it stand out from the rest is the following features:
• Possibility to upload documents from front-end. Any user (depending on permissions set by administrator) is able to upload a file, even guests, and set a price for it. Any other user who tries to download the file will be asked for payment. This means that you can define what user groups are able to upload and sell files on your site.
• Definition of permissions on actions for managing the component based on ACL. In other words you can specify who does what. The permissions you can grant include download a file, upload, change price for a file, change currency of the price, download file without paying or use HTML editor for setting the description of a file.
Demo version doesn't support payments but it can be used as a download/upload manager as long as you set items prices to zero or you allow "free download" to all users.