Anyways, my guess would be 175 but with the new multi kit for exidy 440s and the market being what it is, it could be lower. And since I don't own one, it could be much higher. I have wanted the game for a while, but the most I would give would probably be 100. I think it might be very difficult to piece one together.
I'm no expert on EXIDY boards (or any board for that matter!), but $175 does seem a little low for Chiller. I'm not so sure what all the fascination is with that game, (the gameplay freaks me out a bit) but I know it is definitely one of the more "high demand" machines.
That being said, I'd expect at least $250 to $300 for a working board alone.
last year I saw a Exidy 440 multi board with a buy it now sell for $550 and it sold. I never seen a chiller board for sale on Ebay but seen a chiller cab sell for $1200 really hard to find.