[slavik81]

The words 'material' and 'immaterial' when referring to business costs are usually financial jargon. I presume they described it as an immaterial cost because the expense is small enough that will not have a noticeable impact on their overall financial situation.

> An item is considered material, according to the American Accounting Association, when the knowledge of it would influence the decision of informed investor.

http://simplestudies.com/what-are-the-exceptions-to-basic-ac...