Hi @Klopek, thanks for posting on the Community!
File transfers and shared folders operate differently to one another. Dropbox Professional plans would allow you to create a transfer with up to 100 GB of files inside of it, so that people can download those files.
Shared folders can only be added to accounts with enough quota on them, so for Basic accounts, this would be a maximum of 2 GB (assuming they haven't earned any free quota). It isn't possible to share your quota with another user, unless you're on a Dropbox Business team, and you've added them as a team member.
Hope this helps to clarify matters!