A decade or so back I bought mine for around $300. I have seen the odd one at gunshows for $400 since, although in lesser condition. Plenty have been on the EE for the $700-800 mark over the years, but we can't know the final selling price. They are, of course, restricted since the stock will collapse it to a length shorter than 26 OAL. The way the laws are written, modifying the stock will not change the status, since the work "originally" comes in there somewhere.
The US price has little bearing on these here, since they are neither importable or exportable to there.