each of those sites supply great content at cheap prices on up. original content and copyrights available through most. htl's
PM for Killer Content Discount
productiveplr.com is a plr site w/ good content
Wait...are these PLR sites? If so, I would rather get unique quality content because I would end up having to rewrite the articles anyway. Good list though.
only one is plr, the one that says plr - the others are not
Oh one more -- contentbasics.com