I bought my Stern Dragonfist at an estate auction for an out of business Mechanic shop. It cost me $327 after taxes and fees.
And I picked up a High Speed at an estate sale back in 2006 for $300 because nobody wanted to pay the listed $1,000. The house had to be empty the next day. So I got lucky attending during the last few hours of the sale. The tag had been slashed three times. $1,000 to $800 to $600 and then finally to $400. I offered $300 and they accepted.
So while not the best places to grab a pinball machine, when you do, it can be very cheap.
Marcus