These sites are scams. I have been in retail for over 25 years and decided to take one of these scammers up on their offer to purchase a Canon 5D Mark IV ($3200 camera) for only $400. What I got in the mail was a tiny sim-card adapter worth about $1.00. I had to FIGHT with PayPal to get them to protect me. PayPal said that I received the product. I told them the tracking number that they showed received was for a sim-card adapter worth a $1. They contacted the seller and got jibberish (?) back as response and still sided with the them. Why? Because PayPal knew they were going to eat it, since the web seller was already gone by then.
Consumer electronics have a margin of 12-15%, so if everyone is selling an item at $399, there cost is likely around $340. Apple probably offers even less of a percentage, so an Apple watch at $399 likely costs the retailer around $355. With that knowledge, if you see a newly released product being sold for way below others, it is almost always a scam. Now. if a company releases a new product and still has inventory on older models they will often reduce the price, add a rebate, etc. in order to help move inventory. If after that promotion inventory still sits then they might liquidate it to a seller who specializes in moving product out of the country. These sometimes show up on eBay.
Manuacturers will also sometimes label new products as factory refurbished as a way to move it to a retailer at a lower price, without their other accounts getting upset. When the rep is asked "how can xyz retailer" sell it for $250, when my cost is $350, the rep can say "those are refubished models." Yes, many times refurbished products are actually refurbished. Stores like Best Buy, Walmart, Amazon take back product within 14 or 30 days - most of those products go back to the manufacturer as defective. The MFG then puts them through QC, reparis them if needed, and repackages them as refurbished and usually provides a 90-day warranty on them. Some companies, like Apple, give their refurbished products a full same-as-new warranty - making refurbished products a great way to save some money.
Lastly, sometime a retailer claims factory refurbished, yet the product was never refurbished. They feel it's more attractive to say factory refurbished instead of "used" or "returned". So, in the end, it's the retailers reputation that matters the most.
