If you are really serious about getting windows operating system then you should consult microsoft directly. I am telling you this because it is microsoft that made windows and who better to sell it to you that microsoft themselves. Deoending on your country, microsoft will tell you the exact price. You can then purchase it online or order form microsoft and have it deliverd to you. I only trust things from windows and windows alone. Some of these vendors sell pirated windows and cannot be trusted. Since they are the ones selling them they also do it at their own chosen price which may be epensive than the actual amount. get the software from other online stores that are trusted. Amazon and ebay are good options if you are in need of original software. Also you have to know that pirated software is not that bad. It is not like they have viruses ir something. Just buy the operating system from your local vendor. If they sell you a pirated one then it is not a problem. It will still work fine.