It depends mostly on distribution method. Last sale you could get three cards within minutes of the sale start, so of course prices crashed instantly. Even with a metagame, if that's the case, expect prices to crash (unless the metagame consumes a tremendous amount of them, which is possible but unlikely). However in old sales with voting, the first free card wasn't handed out until a while after the sale started (three votes usually, which took 16 hours or so), which meant there was time for the initial supply to get used up, causing prices to spike. Though what actually caused the prices to spike the most was the store breaking, which it did for the first few sales, which made me a ton (prices would spike up over a dollar a card while no one could list them).
It's been quite a few sales now since cards did anything but drop after the sale started. And they only drop during the sale. So you could game on the metagame, but personally I'd recommend just selling them.
Of course, with the added restrictions, the average user won't be able to just sell their cards on the market instantly any more, so I don't know what effect that will have, so that's a wildcard you might want to factor in. But let's face it, it's been two years since there was a metagame that actually used up cards, so it seems unlikely there will be one this year.
Dante hacking up hordes of zombies, mutated beasts and paramilitary types during a T-virus outbreak or something.
