In terms of a sales manager, think in terms of basing something on margins and not necessarily overall sales, because as a manager he will (or should) be responsible for maintaining healthy margins.
That said, a good overall rule of thumb is 10 percent of revenues, and that may or may not include any overrides he may get from leading a sales team or from those sales people's commissions.
Brad Sugars is the founder of ActionCOACH, the world's number one business coaching firm. As a world-renowned entrepreneur, author and Business Coach, he has helped more than a million clients around the world find business and personal success.
Sugars has owned and operated more than two dozen companies including his main company, ActionCOACH, which has nearly 1,000 offices in 26 countries.