Hello - Behance is totally free for everyone. We do have a premium service called ProSite, that costs money, but comes free with a paid Creative Cloud plan. If that's what you're asking about, then yes, you have to have a paid CC account to get that free, although you can always purchase it as a standalone.
However, note that everything you see on Behance.net is FREE for everyone. It's simply ProSite.com that is our premium service.