Nobody has a clue, but some of us were predicting bottom in the range $280-$285 for quite some time (months). That's the bottom were miners have to stop selling immediately what they mine or turn off their machines. Some smart-asses keep claiming that price has nothing to do with mining which is only partly true, price *is* formed by supply and demand, but they keep forgetting that miners are the bigger part of the supply side. This is not so important when the price is way up and miners can only sell part of their produced BTCs and speculate with the rest, but with the price this low they have to sell right now, there's no margin for risk of BTC falling ever lower and they would end up in red because they've already in debt for the electricity they've consumed. However, when the price goes below the US$ amount already invested in BTC through mining, they have to stop selling and wait for the price to go up to $280 or go out of the business. Simple as that.
And, in fact, this is the "Platonic" ideal. While there is plentiful profit to be made, new miners should keep joining, pushing the difficulty up and pushing the profits down. Satoshi was clearly a believer in the markets.
This is also relevant to an issue people seem to misunderstand about transaction fees. They seem to think that as the block reward falls, transaction fees must rise to match it. Nonsense. Miners leave, difficulty drops and we find a new equilibrium where fees are perhaps higher but do not need to match the previous block rewards.
The absolute genius of it all? In the meantime, the "Easy profits" of mining have lead to the development of first GPU then FPGA then ASIC mining, leading to highly efficient mining so that the transaction fees ultimately will be lower than if we were still sitting jerking around with CPUs. It's like we jumped to internet banking in the mid-1100's instead of erecting huge buildings everywhere and filling them with people and deposit slips. This is capitalism 101.
Unless it all goes down the drain of course. But I know where my money is and it's denominated in BTC.