OKAY, i understand, what does it cost in creating a forum
You will need the following;
1. Domain and webhosting:A webhosting provider will be responsible for keeping and handling your database while domain will be the name of your website just like this forum Xtremeloaded.com.
2. Forum TemplateAfter you might have paid for your domain and hosting you need to design own how your forum should look and that where you will need to look for template/themes that will give you the look and performance you need, you can search for forum free or paid template online.
Note:
Making money online as a blogger is not all about hosting and creating a website but ask yourself how can i attract people to my website, what do i have to offer them.
Hope this helps