This is legit. I am shopping for a new phone, and I have a few I am looking at in the 500$ range (Huawei Mate 10 Pro and the Samsung GS8 Active are top options), but if I decide to do cheaper the LG V20 and the G6 are my choices. Both can be found new in box for under 250.00 if you are patient. The G6 is the tougher of the two to find that cheap, but ebay is your friend when it comes to older phones. So many sellers on there you can get a fantastic device for a great price. I don't think it is the best place for the newer ones, but if you want a back up G6 you can get them and not break the bank.
Case in point is the S8 Active. AT&T still wants your first born to get it. On ebay I am seeing unlocked ones in the 480.00 range NIB.