If the price drops under $280 then you should buy Bitcoin for sure because that price is not high at all.
The prices at the moment are far much higher then what they used to be.
Exactly that would be the best price to invest money in bitcoin but as of now I don't feel that price will go that low and if it does then its an best buying opportunity for all of us.
I also think that under the circumstances the price may drop to such a level although nothing can be excluded and the black Swan can fly suddenly.