Yes. Additional websites under the same NationBuilder account are $9/mo. This means that these websites will be sharing a NationBuilder control panel and database. The pages of your individual websites will be kept separate in the control panel for you to easily manage and make theme adjustments to each website. It's also easy to separate people in your database that are coming in from different websites using tags and saved lists. Additional custom domains for use with your NationBuilder sites are $5/mo each.