Hmmm, I think the worst purchase I have had would be either my Shadow £575 ($900) but it was pretty beat up, hacked boards, couldn't start a game and the DMD wouldn't come on. Or perhaps my Wh20 which was £940 ($1500) and had some smashed plastics, line out on the display, pretty ropey cabinet and wear around the raft inserts.
I guess both of these purchases aren't really bad, especially it in the current market in the UK, but compared to most of the buys I have had they seem high, I just really wanted both of them!
Over 12 years I have had some pretty strong results to be honest.
The highlights are probably an Elektra, which was free. An IJ for £30 ($50) a proto CV for £160 ($250) and like pinballslave, my first bulk purchase, which was £1400 ($2200) which included
Bad Cats
Dr Dude
Diner
F14 Tomcat
Judge Dredd
Getaway HS2
Millionaire
Mousin Around
Street Fighter II
Party Zone
Radical
Silverball Mania x2
Space Invaders
Truck Stop
Super Mario Bros
Mr and Mrs Pacman
Those were certainly the days!