If someone wants simple email, web and plain text documents, for the lowest cost, I set them up with Linux.
I'd encourage those folks to use Macs instead. Although the initial cost of desktop Linux is slightly lower, it's usability as a desktop machine is inferior and it requires more expert maintainence.
My father-in-law is an absolute cheap skate, but fairly patient with techie stuff. I can hand build a cheap PC for less than even a MAC mini (which didn't exist when he got his system.)
And for the three things he does, web, email and a text diary of his trips, there really is not enough difference in usability to amount to a hill of beans. Either way, you have to learn a few things.