The best time to buy is when itsnprice hits low. Justnlike buying some stocks, financial guru teaches us that when its price is low it is the best time. Buy low sell high priciple should be the principle. But that what they said. 
. I buy btc whenever I needed it or whenever of course I have extra money even its price is high. If I needed it I do not consider its values since I needed it right away.
Since we are still in the young stage, any price we can see now is a cheap price and you can say that is a cheap price if only you will believe that bitcoin will succeed in the future, it is actually a simple analysis and we do not need to overthink as in the future the demand will increase which makes the price rise.. I buy btc whenever I needed it or whenever of course I have extra money even its price is high. If I needed it I do not consider its values since I needed it right away.