Pretty Interesting... A quick search for Vectrex in my area:
You can get the multicart for $150 http://losangeles.craigslist.org/lac/vgm/4710689479.html
and someone is selling an entire Vectrex system for $3,650 http://orangecounty.craigslist.org/tag/4702980601.html
Vectrex's aren't worth anywhere close to $3650 the price that guy is quoting is off the wall bonkers. Except for the 3d headset. That is an exceptionally rare piece. Those often times end up in museums and stuff.
Steve's price is fine, nothing special.