According to the information found on the AKVIS Sketch official website, the simple version (either the standalone or the plug-in) cost $72, the Deluxe version costs $89 while the Business edition costs $154. Both the Deluxe and Business include the standalone as well as the plug-in versions.
Also worth mentioning: you can't upgrade from the basic version to the Business one directly; instead, you'll have to first purchase the Deluxe upgrade, then go to Business. Lastly, the basic and the Deluxe edition are for non-commercial use.