Windows users on average pay $21.50 to line the pockets of third party software developers such as Sun Microsystems, Novell and Alcatel-Lucent, according to a calculation by the Software Freedom Law Center (SFLC).
The monies cover legal settlements that Microsoft inked with third party software developers for alleged patent infringements over the past three year. The SFLC in a posting on its website denounced that costs as a "patent tax".
The open source advocacy group provides free legal services to open source developers and is an outspoken opponent of software patents.
"If you run a computer using Windows, you're not just paying for the programmers who put the program together and the corporate operations that brought it to market. You're also paying a hidden tax of well over $20 that Microsoft has had to pay to other patent holders," the group stated.