do you buy a unique domain for your blog in blogspot

[debasis]

its very easy to adding a domain to your blog but i never tried it but i can provide you such links where people have used this method and they have used a unique domains in bloggers.com
plz check following urls

Click Here

Sorry friend another few site links not getting i just forgot their names but don't worry as soon as i remembered all of their names i will provide their links here for demo purposes.
Thanks.

thanks debasis，i know it。but i have not tried adding for my google blog。
i have domain and i have think of doing this because i find my blog somehow on the top of search engine but i dont know if it will be as good as when i use a new domain。

Don't do this mistake if you change your domain then it will suddenly for some period your site's rank will go down google showing your site up because you are using his sub domain.
Thanks.