In reference to key re-seller sites like kinguin that sell windows licences for around 40$. It's generally not a good idea. The keys are legitimate keys that will work, but sometimes the places where they buy up the keys from aren't exactly Microsoft certified sources. They usually get them from a combination of the following-
1: Extra keys from a OEM manufacturer, or other place that buys keys in mass to use that might have extra. (perfectly fine)
2: They bought up a bunch of keys when there was some kind of promotional sale. (rarely happens with Windows keys though)
3: They buy up keys that are normally meant to be free. Such as the ones Microsoft gives away to schools, students, ETC. (Microsoft does not see this as ok, but technically isn't illegal)
4: Sometimes a hacker, or group of hackers, will get a hold of a bunch of different credit card numbers. Then they would buy a ton of keys with them, and then sell them to those sites under the guise of being a OEM system builder as a way of "safely" transferring the money over to themselves.
Ok. Now you buy one of those keys from the site. You use they key. The key will work. However:
The free keys Microsoft gives away will sometimes have a expiration date. Generally around 2 or 3 years. After that the key will stop working.
If they keys were bought with stolen credit cards (some sites are better then others at weeding these guys out), and the owners of these cards dispute the charges and succeed in doing so. Then the key will be revoked.
Most of those sites offer some form of "insurance" you can buy along with the key. So that on the off chance it was gotten through illegitimate means, they'll send you a new free key.......but most of said sites will make you jump through 50 hoops before they'll send you a new key.
NOW- Avoid the Amazon deals for cheap keys at all costs. Unlike the re-seller sites that do some form of verification to make sure the source is legitimate, Amazon isn't doing anything at all to check these alternate retailers that use Amazon as a store front. Avoid them and the key re-seller sites if you have even a remote fear of a key going bad on you.
Edited by SEANIA, 02 May 2016 - 03:04 AM.