What is a fair price to pay for this machine and is it a good game?
Remember that location and condition are everything with these things.
The biggest thing in your favor for buying is your location and the worst thing if your trying to sell is your location, at least on this side of the bay.
So if you are a collector then you can get a good sized game room going for not a lot of money. If you're trying to flip games you might have a hard time of it. There are not a lot of buyers in the area and we are too far from the larger cities to make it worth while for someone that is a collector to make a drive unless it's a really sought after title.
With exception of one pinball machine, which was a specific Kiss machine I bought from a long-time friend who was moving, I've never spent more than a couple of hundred on a pinball machine. I bought a Jurassic Park for $15, Dr. Who for $100, and a Judge Dredd in the same range as the Dr. Who (it's been a while, so I don't remember exactly).
Same for the video games, I think I did an average one time of all of the games I have and it works out to something like $32.50 .
To tell you how bad of a market there is on the video games locally, I bought a Zookeeper for off of Cragslist for $125 a few years ago. It sat for 12 days @ $125 before I bought it. It wasn't a game I was looking for and I bought it to get the monitor before finding out it was something a lot of folks were looking for at the time.
There are not a lot of collectors locally and I've got just about everything I want, so you don't have a lot of competition. There's one other guy in town that buys games and sticks 60-in-one's in them and tries to sell them, but I don't see them moving very well.
Don't get in a hurry or be afraid to walk away from a deal. Make a fair offer and let them sit on it a while of they don't want to come off of the price. Unless it's an A-list pin or rare video game then it will sit until they come down in price or decide not to sell.
All of this info won't help with the specific question you had on the pinball machine, but it gives you a rundown on the trends I've seen over the past 10 years or so of collecting in our area.
-JM