The monthly price for your first RCON instance will always be $11. Any additional servers will be another $3 per month.
We can host the admin interface on one of your domain names (if you own one), or one of ours. We've noticed over time that not many Hell Let Loose groups host their RCON instances behind a domain and SSL. Hosting it on a domain not only looks more professional, it's a lot more secure. This is built into the pricing, we will not allow RCON instances to be accessed through their raw IP addresses.