Any visitor can use the kwn.me site (or any of the alias domains) at no cost. Making a quick short link is free too, and creating a vanity url (short slug) is free too.
Example:
http://example.com/long/url/to/some.php?page=online
Can become:
http://kwn.me/154
And with a slug:
http://kwn.me/chroder
Users with a registered account can get a few moderated privileges, alongside getting theirname.kwn.me (or theirname.any alias domain). This is free and allows one to have a personalized shortening url, with or without a slug.
Example:
http://example.com/long/url/to/some.php?page=online
Can become:
http://john.kwn.me/154
And with a slug:
http://john.kwn.me/chroder
Registered user can upgrade for a fee to a premium account and get unmoderated privileges and ability to add their own domain alias and use the kwn.me engine. This is not free, but very affordable and convinient.
Example: (imagine yourdomain.com)
http://example.com/long/url/to/some.php?page=online
Can become:
http://quicklink.me/154
And with a slug:
http://quicklink.me/chroder