Pricing is hit or miss with early SS - depends on the seller.
I try to price my machines at a fair price.
Sold a Phoenix that was in good shape last month for $500 (boards were updated with new capacitors, etc.), playfield, backglass, and cabinet were nice.
Will have a Williams Contact for sale soon - probably price it at $600 - boards are system 6, new capacitors, some tip 102s, new resistors, NVRAM installed. Playfield is in great shape but will need cleanup and new rubbers. Only downside of the machine is that someone spray painted the cabinet black.