You might see that the Dropbox Community team have been busy working on some major updates to the Community itself! So, here is some info on what’s changed, what’s staying the same and what you can expect from the Dropbox Community overall.
Forum Discussion
Sharing folders without space
I want to accept an invitation to share a folder but dropbox won't let me without buying more space.
what's the deal here? If the owner has the space why can't I accept the invitation, look at it a...
If you have read/write access to a folder then it is also part of your Dropbox and so uses your quota. So yes, regardless of how big the other persons quota is if its a read/write folder you will need to upgrade to view it if you do not have enough space in your account.
If you just need read only access they can use shared links via https://help.dropbox.com/files-folders/view-only-access which will not use your quota.
This is happening because the content of the folder/file you're invited to combined with what you already have in your Dropbox exceeds your space. When invited to a shared folder Dropbox essentially "copies" the files to your Dropbox - this way you can have access to the files offline, etc.
You have few options;
a) you delete some of your files from Dropbox to make space.
a) owner of the shared folder reduces the amount of files/space in the shared folder to fit what you have available on your Dropbox.
c) instead of being invited to a share have the owner send you a link where you can just download the file(s) without adding to Dropbox (but this will not let you easily collaborate if that was the intended purpose of the share)
