That doesn't make sense.
If you buy a pc with win8 -and you have downgrade rights.
What does that mean?
It must mean you are entitled to use Windows 7 instead of win8 that came with it.
Why would you need to buy anything else?
You should just need to find the installation media.
You already paid for a win8 license - you don't want that, so you exchange it for Windows 7. http://www.mydigitallife.info/offici...digital-river/