PageLines is one of the more popular premium WordPress theme developers. Their goal is simple: to make people happy. In order to do that, they have decided to focus more on quality than quantity. And with that said, they have developed the PageLines Framework, a drag-and-drop WordPress theme that lets you build websites visually, without coding. They also run the PageLines Store which provides child themes, plugins and other addons for your website.
Choose a license that lets you use PageLines on as many of your own sites as you want or get the Developer license to use it for your clients. Support and documentation is provided.
Premium WordPress theme sellers typically include support and upgrades with theme purchases. Visit PageLines's website for complete details including the most up-to-date pricing.