自由／开源软件免费吗？

关于自由／开源软件的一种常见想法是认为它总是“免费的”。在某种程度上这种想法是对的。没有真正的自由／开源软件收取用户授权费用。大部分自由／开源软件发行版本（Red Hat，SuSE，Debian 等等）可以免费从因特网上获取。考虑授权费用的话，自由／开源软件几乎总是比私有软件便宜。

但是，授权费用并不是软件包或基础架构的唯一花费。考虑人员开支，硬件需求，机会成本和培训费用也很必要。一个经常使用的概念是总体拥有成本（Total Cost of Ownership, TCO），这些成本给我们最清楚地展示了使用自由／开源软件所节省的花销。（2）

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2 有人认为投资回报率（Return On Investment, ROI）是更好的指标。但是，对于自由／开源软件 ROI 的研究很少，而且 ROI 与 TCO 一样难以衡量，甚至更难。关于 ROI 与 TCO 比较的一篇文章在 http://www.infoworld.com/inforworld/article/03/08/29/34FElinux_1.html

The popular myth surrounding Free/Open Source Software is that it is always “free”—that is, “free of charge.” To a certain degree this is true. No true FOSS application charges a licensing fee for usage. Most FOSS distributions (Red Hat, SuSE, Debian, etc.) can be obtained at no charge off the Internet. On a licensing cost basis, FOSS applications are almost always cheaper than proprietary software.

However, licensing costs are not the only costs of a software package or infrastructure. It is also necessary to consider personnel costs, hardware requirements, opportunity costs and training costs. Often referred to as the Total Cost of Ownership (TCO), these costs give the clearest picture of the savings from using FOSS1.