Is it possible to purchase a website template with Business Catalyst?

There are a few sites that sale BC templates pre-built for you if that is what you are looking for.

Here are two of them: 

Adobe Business Catalyst Templates

TribeVita.com

I believe there are a few other places that sale them and searching Google may turn them up.

Hope this helps.

Most of the template providers are listed in your Partner Portal under Resources > Templates