Can I sell this plugin or give it away?

Since S3Media LinkSafe Lite is a free plugin downloadable from this site, it makes no sense to sell it on. But you can charge money to install and configure the plugin for your web clients, for instance. This is in fact the corner stone of Open Source Software: "Live and let live".
Although we cannot forbid you to post the plugin on your site for download, it is better to link to our download page instead since we always have the latest version available.
Keep in mind that all tutorialson this site are copyright protected, you can only place links to the documentation. This ensures that corrections and additions are up to date.