The costs involved for a website are 1) domain name, 2) web hosting, and 3) website builder/services you may need. Most companies that you buy the domain name from allow you to use the web hosting of your choice. You do need web hosting. As you want to create a social website, it would be a good idea to add SSL to your web hosting too, for a secure connection/data transfer. You can view the costs of the web hosting options and SSL at UltimateWB here: https://www.ultimatewb.com/domain-names-web-hosting . Regarding SSL, also check out this blog post, What is SSL and do you need it? at https://www.ultimatewb.com/blog/503/when-do-you-need-a-secured-server-ssl-certificate-website/ .
Now for your website builder, for the built-in social networking apps you would need the UltimateWB Full version. You can buy this on the Purchase & Download > Buy & Upgrade Software page at https://www.ultimatewb.com/buy .
We have many resources available online so that you can create your own website and we provide free tech support via email and on the forums. You can find video tutorials, the online user manual, support forums, and more, under the Resources tab at ultimatewb.com .
Please feel free to post if you have any further questions.