With all the good news coming out in favor of bitcoin like
Expedia accepting bitcoin etc it's time to buy with the price going down. You will not be so lucky next week. I strongly believe it's going to reach $700 by end of next week!
It's better to buy as soon as possible, but make sure you timing it when the price is down. Then have it traded or invest. I myself, prefer buying on the sale then once back to normal, do the training. That will do.
The price changes everytime, it may goes up now and later goes down. When someone fells like buying or selling, it is all up to him, it depends on what choice he wants. So for me, I think it us better to buy now while the price is low and we can afford buying it, and hold it till the right time comes.