Not sure if this covers your question, as the OP said "the same computer with Windows and Linux available" but at least you can probably find the equivalent Linux machines here and then compare to the previously found Windows systems.
Customize the one that is currently listed at $579. It has an i3-9100 processor and switching from Windows 10 Pro to Ubuntu will subtract $109.27. But if you then switch the processor to the Xeon E-2246G, then changing from Windows 10 Pro for Workstations to Ubuntu is a price reduction of $264.36!
As an aside, I find it hilarious (and nice) that you can save a couple dollars by specifying no keyboard or mouse. Sometimes, you'll even see the option to have them skip shipping you a power cord for $2 off or something.