I got XP Home from eBay for around $80. Pro isn't much more. Although there are a few complications I have with this copy of XP, I would just recommend buying one from a store like Newegg.
It is an OEM disk. The only thing they have on it is the OS. It's not a restore CD or a driver CD.
Did you bother to click the link that said: "To learn more: Click here"? Well click here: http://www.edirectsoftware.com/oem.php It explains pretty clearly what OEM software is.