I completely agree about the price. The problem is, the cost of materials and the time it takes to make the custom parts and put the thing together.
Even the wiring harnesses are assembled by hand. And I might add, there is one guy making them from start to finish - he machines the parts - Assembles the unit - builds the wiring harnesses - and packs it. The process is about 6-8 hours per unit - end to end.
I've always thought it was a very high end device, but that said, I just bought a $200 topper for my AC/DC so it's becoming a "Normal" price now.
And, I might add, the guy who stole our device name and sold them for $100 to make it impossible for us to sell ours has raised his price to $300. In his unit, you get a piece of machined aluminum, a servo motor, and a wire that connects it to the light. When the light comes on, it moves in a jerky pattern.
Ours has a multiple machined steel parts with bronze bushings, an opto to determine when the device is forward, a real motor, adjustable mounting to account for changes in the plastic of the Dalek over the years, a wiring harness that can be installed without cutting or splicing a single wire. The Game ROM controls the movement of the head. Also, if you go into diagnostics on your game, there is actually diagnostics for our unit already in the game. That's because of the opto. The engineering took a long time and the one in my game (which was the first) has worked flawlessly for 13 years!
The installation manual is at: http://pinballobsession.com/PDFs/Wobble10a.pdf and you can see the build quality in the pictures.
Unfortunately, it's just an expensive device to make and we really appreciate all of the people who purchased them over the years.