In most cases, there are no additional charges. And yes, these are one time fees and once the website is paid in full, you OWN IT!
There are some optional Add-in available (see below).
Pricing does not include Domain Name Purchase, SSL Certificate, Hosting or additional fees for PRO Plugins that do not come with your theme.
Extra add-ins available for your website:
Advanced Forms | Advanced YouTube Integration | Image or Video Slider Integration | Plugins That Require Pro | Yoast SEO Premium | Photo Galleries | Purchase or Subscription | e-Commerce | FlexMLS or IDX Integration
Hourly Rate: $35.00/HR
Logo Design | Search Engine Optimization (SEO) | Pay-Per-Click Campaigns | Blogging | Social Media Management & Marketing