#3
The one Ebay listing I found said they were asking $450 and accepted the best offer. So I would imagine that would be a OK price
#4
I kind of want one. That was my first electric back in 78 was actually a very nice guitar at the time i had a few effects modules for it. They are great guitars and a bit quirky. The MPC line had swappable modules that had effects I had a phaser, flanger, distortion and a tank sound which was a EQ effect. Very innovative for that time and fairly well executed overall.

I think if you play it for more than a few hours you will grow a 70's porn stach and your pants turn into bell bottoms.