I'd say it's worth approximately one arm and one leg.
4000 is worth about £500, 060 the same, PIV about 350, Deneb about 250, Goldengate about 250-350, the test about 50-100 each Amiga board (PC boards are worth nothing).
Not $1000 for a Goldengate, no.... if it did happen once (I didn't see it) it was a fluke.