Arcade games

Just curious... There's a shop in Coalville, I'm not sure what it sells (maybe it sells games consoles; maybe it's an amusement arcade; maybe both). In the window this weekend were two machines that caught my eye: an original Space Invaders machine from 1978, priced at 895 pounds; and a pinball machine from 1979 (branded "Gottlieb") for an almost-as-unreasonable 495 pounds. (I think at current exchange rates that's about $1300 and $700 US) As I was walking home, failing to hum the Space Invaders song, I wondered what sort of an active market is there for such machines? The prices looked high enough that they must be aiming at serious collectors, or possibly innkeepers who want to create a retro-seventies atmosphere. So do people here know about the classic arcade game market? Are my neighbours of a couple of blocks away being overoptimistic with their prices? Philip. PS What I remember from the period was the many, many attempts to write Invaders-style games in BASIC on the PET and other home computers. And my friend Matthew, after we'd borrowed a Sinclair ZX81 and experimented for a week or two, shutting himself away and writing a quite good one for that machine in machine code - I helped with the BASIC shell that built the initial screen display. And wiring a phone earpiece to the PET user port to hear the sound effects on the Commodore invaders program. And so on... PPS has anyone preserved the Space Invaders song? I sincerely hope not.