My money is on 'junk', mostly because the seller has made so little effort to put in a decent description or take decent photos.
For example: What are the 21 bikes? I've spotted two AG100s/175s, and what appears to be a rough-as-guts Z250 deserves its own photo, so I hold low hopes that any of the remaining 18 are worth pissing on...
And three pics of old tyres. Woohoo...? If there are decent wheels in there, or just rusty old shit that's been left out in the weather?
Etc.
At $500, you'd probably be able to find value in it, but you'd have to spend a lot of time reselling it (not to mention the time spent collecting it all).
Of course, there's always the chance that there's a Phantom or YZ360A sitting in there, but I wouldn't be holding my breath....