There are actually a number of printings of Aether Vial, three of which are already foil: the original Darksteel printing, the Modern Masters reprint, and the From the Vault: Relics printing. People really aren’t fond of the FTV foiling process, so that is the cheapest version at around $50. The Modern Masters foil hangs around $60, and the Darksteel foil is around $70. The first pre-orders for the Masterpiece Aether Vial have been in the $120 range due to the uniqueness and extreme rarity of this version.
Since this is a card you really need four of at a time, it’s understandable why the pre-order price on this card is so high. It’s probably going to easily be one of the most sought-after Masterpiece cards in the set. Occasionally, the Vial sneaks into some Commander decks, too, so there will be those out there that also want a single copy, particularly Sliver Tribal decks. This is a really good card. Most people will likely want to either keep their copies or trade them down to the cheaper pre-existing foils. While you shouldn’t buy-in super early, and perhaps trade them out because of the hype, Aether Vial foils are just always going to be good to have, no matter what the printing.