a big problem in pinball buying/selling is this. ..... a semi-wreck (The purple colour is a big hint towards this category) should only cost about a quarter or a third of what a Class 1 machine is worth. To get a machine to REAL Class 1 condition usually involves mega time, and a lot of dollars spent. When in this shape they have to be worth at least $3000.
 ............ The trouble is, occasional (or greedy) sellers want and often ask 'top dollar' for machines that are in Class 3 or 4 condition. Try and get the seller to acknowledge the true condition of the machine, especially with you standing over it. Then you may be able to get a more sensible approach.
I've restored machines for a long time, and know the real value, and superior quality of such machines. Sellers who have sad arsed versions of any game need to be approached with caution, especially when the PRICE and CONDITION have not much in common. Good luck.