if it's below 200$ then of course it's good time to buy, if 300$, hen it's good time too, because price now is 430$ and still rising, so later might be too late for good price to buy
any price lower than $400 is an awesome deal but the problem is not what price is good, the problem is that if the price is going to go there before the next rise.
which i doubt it happens, the price is not going to under $400 unless someone pulls a Mike Hearn