NewEgg sells
Win XP Pro OEM for $141. (You have to buy a piece of hardware to buy OEM software, but they conviently link you to a $0.99 power splitter cable to include with your purchase!) Or
Win XP Home OEM for $90.And, from NewEgg, I would guarantee that they are legit legal OEM versions. I use them quite a bit for buying hardware components, and they have always come through with exactly the product advertised at exactly the price advertised. (They don't try to sell an OEM part as a retail, or an imitation as an OEM, or any junk like that.)
The one time I did have a problem (I got a DOA CD/RW despite it being sealed in original packing) they were very prompt with the exchange and picked up shipping. So, in short, I highly recommend them as a US company to deal with. I don't know how overseas shipping would work, though.
