After much research I found my answer. According to Microsoft you only need to purchase the media one time per location. For example, I have 2 computers, one running XP home and one XP pro. I need the media disk for each. I can buy just the COA for XP pro and sell my copy of XP home, giving me 2 copies of XP pro, but only one media copy at this location. Just a heads up to everyone who wants to do it the legal, morally correct way, but also not pay extra.
Told you so.
