well when you signed up for the site did you sign up for the SUBDOMAIN as that is free
if you want a DOMAIN you have to pay for that
so why not upgrade your site from the free one you have if that is what you want
quite a few people here when signing up for a site hit the domain and think that is what they get free but you have to pay for it and you can use free hosting or upgrade your hosting
But if you want to upgrade your Subdomain you have you are welcome to do that
the subdomain is Free as said you have Paid for NOTHING yet
