Currently the price of windows 7 is very cheap. If you plan on building for the reason of saving money vs buying a prebuilt the window may be pretty small. At least for buying your operating system. Windows 8 will soon come out and a full install will be around 400$. Seeing as some people's budgets are in the range of 450-1000$, 400 will take a huge chunk out of what you are trying to build.
I had to buy a copy myself (windows 7) and I tried to look for a Windows Vista as I was hoping it was cheaper. They stopped selling it. I couldn't find it anywhere. I ended up buying a bootleg version of windows 7 (well it was advertised as geniune... too good to be true it probably is.. Bought the full version when the price dropped to 200$. Anyway to avoid all that hastle yourself, buy now.
Suggestion... buy windows 7 as quick as you can even if you have to save up for the rest of the parts.
I had to buy a copy myself (windows 7) and I tried to look for a Windows Vista as I was hoping it was cheaper. They stopped selling it. I couldn't find it anywhere. I ended up buying a bootleg version of windows 7 (well it was advertised as geniune... too good to be true it probably is.. Bought the full version when the price dropped to 200$. Anyway to avoid all that hastle yourself, buy now.
Suggestion... buy windows 7 as quick as you can even if you have to save up for the rest of the parts.