moving on from windows xp. buy win7 or win8, best deal ?

OK, so I'm thinking about acting brash and moving on from windows xp.

I'd like to spend a minimal amount of money doing it.
I'm particularly looking at the most economical way to do it.
Might prefer to go to win7 vs win8, but will go with whatever I can do cheapest.
Its pretty complicated with all the versions and ways to buy it.

Are there special deals to find? Are deals more likely to come up for 7 or 8?
I'm open to buying a legitimate disc on ebay or downloading direct from microsoft.


complications: while I want to spend the least amount of money, might consider buying a whole computer or central components, (cpu,ram,mb),
if I can get a real good deal with win7 or win8 included. I would only want to spend a few hundred dollars though for the whole thing.
I'm running a fairly old core2duo system w 4 gigs, that actually isn't even completely stable during long gaming sessions, but its good enough for me still.
Also I'm cautious about getting an OEM version as I am likely to want to upgrade my computer within a couple years if not sooner.
My video card is a nvida GTS 450, which I find sufficient and not in a rush to upgrade.

Of course there is also the old thinkpad running xp.
I won't worry about that one, unless of course I can get a deal on 2 or 3 copies i cant turn down.

Suggestions? Thanks.

Any legit version of Windows XP or newer can get a $40 upgrade to Windows 8 before the end of the year. Anything else and you really should decide if you're going to stick with the same hardware or not, and whether a "not" includes building a new system from scratch.

Have you perused the Help Me Build My PC Catch-All thread?

I should have noted, an OS software upgrade is not an option for me.

I haven't looked at the Help Me Build My PC Catch-All thread?, thanks for the suggestions.
Anyone know of any XP deals that i could then upgrade to 8?
Again, just looking for the cheapest way to do it.

Anyone have any experience purchasing a legit copy of XP on ebay?