A:Answer Much of the cost revolves around the the type of media used to load the OS. As an example, a download install would be much less expensive than say a DVDROM or flash drive, which is the most expensive. Now, there are other factors too. As an example, do you want a 32 bit, 32/64 bit media, Home version verses the Pro version. It all factors together. Pick your solution, and make a choice. Now, there are solutions on websites that cost quite a bit less, but you run the risk of purchasing a "knock-off". There are people out there scamming folks into purchasing what you think is Windows 10 Pro 32/64 bit software, but only getting a refinished DVD of a previous version and no valid Key. Best Buy honors replacements of products they sell. If there is a problem with the purchased media they will replace it.