GnomGnomGnom wrote:it is because someone bought out all the copies and is trying to corner the market.
unfortunately it is doomed to fail because there is no sign that mono black will have any significance in the modern meta. There are plenty of copies left on non-tcg websites and EU, etc.. that it will simply not sustain itself. sell yours now or trade them away if you have them because they are just going to go back down to ~15-20 dollars in the long run.
artificial price hikes often have a similar trajectory. Chandra, Pyromaster shot up from ~10 to ~30 dollars in a few days with just whispers of results. In actuality it did not get as much play as it was hyped and dropped back down to ~10-15.
Actually, Chandra spiked because it was in Reid Duke's Jund deck for GP Detroit that made it into the finals. Wizards did not broadcast that GP. It is still at $20 tcg-mid.
Your statement that the spike is because of a buyout might be true, but that is an assumption. Another assumption I would make is that people are testing mono-black in modern to find out if it's success in standard can be ported over. Whether or not the deck produces results does not matter as long as there are enough players wanting the card and not enough in supply, the high price will remain. Is it sustainable in the long run? maybe, maybe not. Also, a lot of casual players like to relive the MBC days. =P