Years ago I ran in to a deal on an ATN rifle scope (no night vision capability) at less than half price. FFP, simple reticle with wind holds and one corner with ranging to 600 yds or whatever on deer size animals, lead free glass, you get the picture.
I called the place, talked to the seller, and he says, paraphrasing, "it's a great concept, awesome features and price, but it sucks. 1/3 returned defective and the dirtiest glass he'd ever seen".
Same guy sold me my first Sightron that day at a better price and from that suggestion I believe he knew what he was talking about. Nothing comes for free so beware the too good to be true "deal".