The catalog value is a little over $100 for the set in MNH. If the strip of 3 (1074a) is intact and unfolded, you can add another $50 or so. So there is no basis for the price to be $250.
Is there actually any bidding activity on that sale? Other dealers are selling that set (including the intact 1074a) for below catalog. Unless there is something special about that particular lot, it makes no sense to bid on it; and I would pretty much never buy something from someone who tried to pull that kind of stunt.
There always sellers on
ebay that are overpricing their wares. And there are always foolish buyers on
ebay that will pay those silly prices. Knowledge is a key, for both buyer and seller. I don't like sellers who try the "fishing for fools" method.