Using godaddy domain to a wordpress.com site

Hi everyone i’m new to wordpress, so the problem is that i created a new site with animadomain.wordpress.com as address and bought animadomain.com from godaddy and i’m not sure how to use it on my wordpress.com site.

i searched the internet and found that i must map the domain and when i did it the wordpress.com ask me to $13 for it which i didn’t do because i already bought the domain on godaddy. can someone help or explain what’s going on?

ps: i don’t want to use the godaddy wordpress hosting

Thanks