Totally free. You'll have to purchase "domain points" to add more than 2 domains. It supports DNS but for name servers you need to pay or be premium or something like that. I'm using it and so far it's alright, does the job for my servers. Though this isn't really a "domain" (it's not a TLD), and rather a subdomain. But it's nice and short.

This post has been edited by IntensiveBytes: Mar 18 2013, 03:09 PM

^

True. These are considered subdomains, so your domain is actually part of a subdomain that isn't really 100% trusted. Your domain isn't even yours. The site can anytime take it away from you, and such. It's not safe. Purchasing a domain is the best decision to make unless you're just testing things.