This section of the forum is for discussing the business and finance issues of the t-shirt industry. Which business structure to use (sole proprietor, LLC, S Corp, etc), how to handle billing, where to register your business and get the proper licensing, etc.
10% - 15% sounds about right. I agree that it would be nice to have 10% to a point and then 15% after a certain target -- that definitely gives your sales force a bit of an incentive to work harder!