Kurator’s free version lets you use all the functionality and add up to 100 links. You will need to upgrade in order to add an unlimited number of links and folders.
The free version lets you add one KBucket file and one Sync Folder.
You can upgrade Kurator from your Kurator Bookmark Manager menu. Simply click on the Account tab in the top right of the menu and upgrade to Standard (3 KBucket and 3 Sync Folders), Pro (10 KBucket and 10 sync folders), and Agency (unlimited) versions.