You do not have to have a huge idle money to invest, a lot of people forget that savings is a way to make money in bitcoin too. If you get your salary per month, just after getting that money, invest every month. If you do that every single month for ten years, I do not care how late you think you are to bitcoin, you are going to make some good decent amount of money. This will not make you rich overnight, but after ten years of doing this, or twenty years of doing this, you are going to be quite wealthy I believe. Of course this is just a guess, or more like hope, because I am trying to do it and I hope it works out.