We do have an advertising program called WordAds.
Advertising outside of WordAds at WordPress.com is not allowed.
There are no restrictions if you setup a self-hosted WordPress.org blog instead of a WordPress.com blog, but there are some added responsibilities.
The domain registration (including private registration) is $26 a year, without private registration it's $18 a year. Currently you have a $99 bundle. If you want I can cancel/refund the bundle and leave the domain registered under your account.
To point the domain you registered at WordPress.com to another server (hosting service), please follow the instructions here:
Note you will need to obtain the name server values from your current host. You should be able to find them on their support documentation, or contact them and ask for the information. (Name servers may be referred as "nameservers" or "NS records" instead.)
Hope this helps - let us know if you have any more questions!