450. I'll be the devil's advocate on this. I bought my Top Card early in my collecting career 6 years ago, and sold it for same as I bought it: 200. And the backglass was nicer while the playfield and cab were worse. It's a fun game, but it's a BORING game very quickly, as the standups are too far away to provide much randomness. Also, in 6 years, I've never heard ANYONE say "HOT DAMN A TOP CARD, I'M BUYING THAT RIGHT NOW!"
If you're gonna pay 600, the ONLY reason would be because you want a tolerable, original cabinet...and that's one of the *very* few I've seen on a Top Card that doesn't make me want to retch.