Is MS Server cheaper thanLinux in RadioShack?

I read from Microsoft that its Server is 20% to 50% cheaper than Linux in Radio Shack. Is this a hoax? I am a professional accountant, I want line for line of cost comparison between the two. Otherwise, it’s unbelievable!! Has Mircosoft taken into account the other free softwares that comes with Linux? Even if it’s true for the time being, wait till Bill puts a leash on your neck!! Will somebody clarify the cost figures for me?