Originally Posted By: NucleusG4
Correction... no. They don't need DB to download a file.

Sharing a read-only link instead

You can also link to files and folders in your Dropbox with a simple click. Friends and colleagues who click the link get a preview of the file in their browser with an option to download it - even if they don't have a Dropbox of their own. To see links in action, head over to this features page or learn how to make a link here.

But they can't upload.

DropBox takes up very little space and resources, it's free, and you could set up shared folders for each client (only that client has access to that specific folder), it's free, and files automagically sync between you and the client. It's free.