Simple Themes is a provider of commercial WordPress themes. Their focus is on creating lightweight, customizable, search engine optimized themes with unique designs and W3C valid code. Their pricing model is membership-based but the cost of their least expensive plan is about the same as the cost of an individual theme from other sellers and includes unlimited use of all themes. Simple Themes provides customer support via their forums.
Premium WordPress theme sellers typically include support and upgrades with theme purchases. Visit Simple Themes's website for complete details including the most up-to-date pricing.