joining blogs and sites

hay

if you want to keep the site hosted at wp.com it will cost you $13 a year see:

https://en.support.wordpress.com/domains/
https://en.support.wordpress.com/domains/map-existing-domain/

and basically once you’ve pointed your domain names at wordpress follow instuctions above map existing domain

go to
https://absolutelyeverythingalmost.wordpress.com/wp-admin/paid-upgrades.php?page=domains

and add your domain / buy the upgrade

You need to discuss this on WordPress.com’s forums https://en.forums.wordpress.com/