However, I'd say that if someone has low income and can barely make ends meet, there's probably no good way to invest in Bitcoin. Because I firmly believe that people should only invest what they can afford to lose.
I was having this mindset before but after checking the history of Bitcoin in terms of the growth in price, I think that statement is not entirely correct. This is because no one loses money to Bitcoin if the investment is held for at least 5 years. Besides, the only time you get to lose money in Bitcoin is when you sell. So instead of advising people to invest only what they can lose, we can say that people should invest what they can afford to hold for long time. In other words, they should invest money they have no urgent need of and can afford to leave them there for some years. Consequently, I see Bitcoin as a good option for retirement savings and this is where the DCA method can be very useful for those earning regular income such as salary.