According to section 6.2.1: "Commercial tools are available at a wide range of prices and with varying costs structures. Payment models include one-time purchase for a flat-rate price, prices that depend on the system size or the operating and/or development environment, License price plus regular maintenance charges, leasing, and so on. Selecting an appropriate licensing model is part of the tool selection process. In addition to the cost of the software itself, you also have to consider administration and operating costs, as well as the cost of learning and training. Training costs alone can far exceed the purchase price of many software licenses."
Source:
Gharbi, Mahbouba; Koschel, Arne; Rausch, Andreas; Starke, Gernot. Software Architecture Fundamentals: A Study Guide for the Certified Professional for Software Architecture® – Foundation Level – iSAQB compliant . Rocky Nook. Kindle Edition.