The tell-tale signs seem obvious in retrospect, but even the best of us can be fooled sometimes:

1. The lowest price, by quite a bit 2. An eBay "classified" ad, which doesn't support purchasing through eBay (why does eBay even offer this?) 3. Some sort of rug pull at the last minute, to make the payment non-refundable.

I'll give a detailed story: I found a Mac Studio M3 Ultra for ~$500 less than the closest "Buy it Now" machine. Emailed the seller, which requires filling out a basic form, and they responded that they would send a PayPal invoice once I confirmed my PayPal and shipping address. Now, if you do a minimum amount of research on these "classified" ads, this is generally recommended as the safest option to complete the transaction, as PayPal will allow you to confirm the product before releasing the funds to the seller. However, I noticed that the seller replied/quoted my message and the form was translated to German, although the product was listed in Chicago. Hint #1. I confirmed my PayPal info anyway, and they responded that due to a "PayPal issue", I'd have to send them a "gift" payment first. Hint #2, and at this point I reported the account. eBay emailed me a couple hours later warning me that the account had been hijacked and was being used for scams.

Going back to the search results, there are several of these Macs, all listed below market value, all as "classified" ads, and probably all either scam accounts or account take-overs.

So, be aware and use common sense.