can someone explain those chinese dealers?
 

If you look at ebay, you'll see those Asian dealers who sell bulk figures. Like 10 star wars figs (all the same) for $10, or similar. All loose.

Are these k nock offs? or overruns they buy from the factory? or made after hours and sold out the3 back door? or what?

The Starwars ones might be bootleg, but I haven't really gotten a set-I kept on being outbid. For the others, some claim they are backdoor deals. I did get a few factory 'defects' (plastic flashes, mismatched parts, missing paints, etc). Not too bad for the prices.

And there are outright bootleg figures that use inferior plastics.

I've bought a few from someone there, which seem to be OK. Possibly not as well painted. I wasn't all that concerned about IP issues as I just cut them up for parts to make something totally different. But for example there seems to be 10,000 Russian soldiers from the Last Indiana Jones film which seem to make reasonable 'male figure' fodder.