I have a soft spot for this game. It was the first 3D fighter and shaped the foundation for every 3D fighting game since. With that said, I can admit it hasn't aged well. Unlike, say, part 2. If you think 2 is a horrible game now days, you're a philistine.
I got my very routed, very average dedicated VF1 unit for about 100 at an auction in the mid 2K's, where no one wanted it and I jumped the gun by 50 bucks too much to win it. There are two big money elements to a VF1 you need to consider when buying one:
1) The side/CP art: Replacement CP/Side Art is non-existent. NOS seems to be damned near impossible to locate for some reason.
It's one of those NOS art packages that everyone could swear they've seen a dozen replacement CP art sheets laying around somewhere...but it winds up being for VF2, 3 or 4. If it isn't rare, then it has an uncanny way of not appearing when I am looking for it.
There's a mirror material associated with this art as well, which may explain why no one is repro'ing it (other than low demand).
This was a huge bummer when I first got my VF1, because I planned on completely stripping and refurbishing the thing (as well as finding a way to swap between 1 and 2)...but now it is just all about keeping the scratched up original artwork as unmolested as possible.
2) The monitor. Self explanatory in that the game requires a Med. Res monitor.
The marquee and monitor bezel are a dime-a-dozen on eBay, since this game was typically converted to 2 or parted out. They are glass, however, which is cool...unless one falls on your face while moving the game (which happened to me).
The PCB is huge and is in a giant, heavy cage. Like the marquee/bezel, the PCB can be easily found...but weight is a major issue when shipping comes into play.
At 500+, it needs to be the best VF1 ever. Perfect side/CP art and a monitor that won't quit. Or Yu Suzuki's personal machine. There are just too many used/scratched up VF1's around to command anything close to 500.