It'll eventually stabilize to the maximum amount of profit practically possible per 100 mist, which happens to be doing 2 FSC runs a day for ~22k. Obviously, it most likely won't legitimately reach that high because everyone who isn't grinding away at FSC keeps it low. The price falls a fair amount every time OOO does a CE promotion, but the only way to make a long-lasting fall of the market is to insert a whole lot of new players into the system. For example, when Steam was integrated, the CE price practically collapsed to 4k. This is due to a sudden demand for cheap CE and a whole lot of players who were willing to shell out real money for it. So, unless you pay for CE or suggest some miracle idea to introduce a crap-ton of players, you're going to have to get CE the hard way.

Supposedly, there's going to be a promo following the guild halls update. The sudden combo of promo + big update will hopefully shoot the ce price straight down into the ground for about a week or more. Seeing as guild halls might be using crowns for their upgrades, some guilds might resort to selling energy for money, causing a lot of supply and less than equivalent demand. So it could be a win/lose situation.