Many people buy used devices all the time. They cost a lot less than a brand new device, but offer the same product.
However there are a couple of problems when it comes to buying a second hand device. A side from the visual aspects or any damages, there is a thing called blacklist.
It is a huge worldwide database which blocks any signal for a given IMEI number. For example an iPhone from AT&T that gets blacklisted, will not work with any USA carrier. You won't be able to use Sprint, Verizon or any other network.
However outside of the USA the device will work fine. The reason is that the blacklisted works only in the given region.
Now you can think that it is not so bad, I can still watch movies on the device, listen o music or play games. That is correct however the problem might get bigger than you think.
Blacklisted device that was reported to the carrier or the police can be tracked down, in which case the proper authorities can take the device, without any refund.
That is why we always recommend using websites like IMEI24.com in order to check the IMEI before the order.
Please remember that any used device, can give you many problems, blacklist being only one of them. If for any reason the seller doesn't want to provide the IMEI number, or doesn't know the phone's back story, don't buy it.
There are a lot of different offers on the market, you will find a better one without any problems.