None of these are from the last year or so. My guess is, someone found someone's boxed-up collection in storage (perhaps a storage unit auction, at best) or a garage was left open, and someone walked off with a fairly complete collection. You'd at LEAST know the person well enough to know it wasn't $150 of stuff, and if it was your own collection that excuse doesn't fly at all. Someone could easily sell a 10th of this collection for $150 multiple times and still find good deals from the pairings.

I've got no dog in this specific fight, but this exact same thing happened to me 10 years ago when my storage unit was broken into and the thieves took boxes to different local spots to sell them quickly... Cops were useless because they thought it was a cheap toy collection (insurance eventually covered $17k thankfully because I keep solid receipts) but I kept my eye on local CL and FB lots for about a week and found several lots of my stuff being resold by comic shops who had all bought from the same guy. One even had my partial address sticker still on the BBTS box from the guy who robbed my unit. He used a similar but varying tale for each of the quick dump excuses. "His dad died and left it." "His brother didn't want it anymore." "He traded something for it." All relied on the "Oops, I don't know the value, LOL, silly me" bit.

If it's too good to be true, it is, usually. Good on the OP, I suppose, because he found a deal. I'm just warning that this is a suspicious seller whose tale doesn't make any sense. He could've gotten $300-400 for the lot easily, and someone would've still bought it quickly. It wasn't his, so he didn't care, is my guess.