I know a lot of places where you can get free.com/.net domains.
URL/Conditions
http://www.domain-4free.com / You must already have an existing URL
http://www.fanku.net / You must already have an existing URL
http://www.elwiki.com / You must register for an elwiki.com subdomain, then once you have 10 pages of it, you e-mail the owner and the owner will give you the free.com/.net that you want. But you don't own it, the owner does.
There's always a catch, but the places that you get a free domain without doing as much work are domain forums like Eukhost.com!