Getting used brass isn't a problem provided you deal with someone who isn't trying to rip you off. I sometimes sell brass on here and I'm honest about it and include pictures. The guy selling that trashed .338 brass was just selling his garbage hoping you'd be too dumb or ignorant to know the difference. That brass would have gone in my recycle bucket for sure and I've discarded brass for less. That's NOT 1x brass! FGGM comes up often enough as 1x and usually, almost always, comes in the original box. I've got a good bit it turns out, and pretty much all is in the boxes. 1x brass should look basically new. The rims shouldn't show any use at all, maybe ONE extractor mark.
I've bought used brass, I get a lot of it that way in fact. When I get military LC brass, I either get it from the military auctions or a smaller lot from someone else who got a lot at auction. Prices are low. But even being 1x, the brass almost always includes MG brass and it can be damaged or destroyed in that one shot. You gotta weed those out and write 'em off. I'm working through two drums of .50BMG LC brass, all fired through an M2HB, and I run into several cases out of a few hundred that get discarded. Maybe more than that. Cracked necks, dented shoulders, dented body, etc. With 5.56, same thing, the SAW trashes brass sometimes. You gotta pay attention.
But with small lots? I'd want pictures. I'd wanna know why he's selling 1x brass, because for reloaders that's what you WANT, the 1x stuff out of your rifle. You'll have to full length size it, then fire it in your rifle, THEN you can go about sizing it to your rifle. Unless you just use SAAMI specs. If the guy is selling small lots of 1x brass, then it should be coming in the original ammunition box. That's how it's usually sold. If the guy reloads, I'd be wary, again because of that 1x fired thing --that brass is more valuable to the owner than even new brass! So if the guy reloads, I tend to shy away.
It's certainly a buyer beware, but if someone screws you, make sure to list 'em in the good/bad guys thread. Those cases are ready to come apart and he knew that when he sent 'em to you. I'd demand a refund first, then resort to that thread, maybe talk to a moderator about kicking his ass off if that's the best he can do for other members. That shit isn't too welcome around here, and people around here don't take to kindly to ripoffs and scams, especially from other members. We generally have a good thing going here, good people, honest people. We need to keep it that way, so report his ass to someone (not Lowlight, he's busy enough) if it happened here. Good luck.
I buy my brass new from Lapua. I get it in 1000rd. cases and for .308 it brings the price down to something like $60 per 100 or $600 per 1000. .338 costs more, yeah, but it's still cheaper to get it that way than any other way.