There are many website which offer free domain names for some time.You can register and try them
http://www.co.cc/

you can register 3 domains as a free member and 100 domains if you pay them a fee of about $10
http://www.eu.tv/

This is a new domain and you can register 3 domains for free and then you must pay.
http://www.co.tv/
you can register 3 domains for free and pay from your 4th domain

There are many others
http://freedomain.co.nr/
http://smartdots.com/
http://www.cydots.com/

How To Setup CO.CC domain For ur blog