I'm not sure what you mean. If you have a domain associated to blogspot, you can park it but such action needs change your domain nameservers to those of the parking service so no more blog will be associated to it. If you have a blog that reads anything.blogspost.com, you can't park it because it's against Google TOS
Google give blogger for free. I wonder what will be the Google action if they found out someone selling their blogspot domain.