Its not that best buy time to buy. Because the value is not that low. And you can see that the value is rising slowly.
And that is very good for the people who already has made an investment in Bitcoin. So if you wanna buy you should have to wait.
But we can't wait for a price that we can't know if it will arrive some day, that is why I think all the time is a good time to buy bitcoin (especially when its price is below the $500 level (taking into account that a $1000 target is perfectly possible).