Difference between two version of windows 8

What is the difference between these 2 versions of windows?





One is for the OEM like Hp, dell etc. but when you buy windows 8.1 retail I think you get the 32 and 64 bit versions...yeah take that lightly I'm not completely sure

System builder is like what cyberpower would use, OEM is for people like HP, Upgrade is for people with XP/Vista/7/8 as a previous version, And the full version would be one that can just install on all PCs, probs a OEM one. Just get an upgrade edition if you are on W7

I dont currently have any version of windows and i am building a PC from scratch

In your situation I'd go with the full version as it may have less problems if you move it to another computer.  And it's only 8 dollars more.

I'm buying all my parts during Black Friday / cyber Monday, what kind of sale could I possibly get based on past sales around that time?

That price is as cheap as I have seen on a retail site for a full version of Windows.  You can sometimes go on ebay and catch a great deal (but always be careful on ebay).  But honestly that is a very good price.  I got a good deal and paid 70 dollars for the OEM but that was a while ago.  That was the OEM version.  I would snatch that up soon if I were you you will not (IMHO) find it much cheaper if at all (Microsoft could always surprise but I doubt it).