If you are putting 100 a month in bitcoin then sudden drop of prices will not be the issue. Even if there occurs a price drop deeper than usual bitcoin will recover in due course and cover those losses. I was referring to the price drop from 4800 dollars to the 3300 dollars few weeks ago. Now bitcoin is at 7100 dollars. Thus even if you decide to put your one week salary or 100 dollars per month is not that bad. In the long run that will give you better results than any other crypto.
With crypto it is very dangerous to have the long term relation. They are good for quick money but in long run it is bitcoin and bitcoin only.