Your own desire is the biggest thing, if you have a real desire, everything is possible, people can invest in Bitcoin even if they want to, even with their low income, for this you just need proper financial management. But yes, those whose income is very limited, they should find new sources of income before investing directly, above all, you must be much more prosperous in terms of your own source of income, people can easily create different sources of income if they want, all you need is willpower. A truly interested person will first prepare everything that is needed for Bitcoin investment, if he moves forward with patience, planning, and complete faith in Bitcoin.
This is just the point bro, people will always do what they truly want, no matter how difficult it seems, as long as the will or desire is there, they might go the extreme route just to achieve it.
Their is a saying in my country that says;
if you think, your salary is too small for you to be investing, just be ready to work all the days of your life.So as long as you are doing something that is paying you either weekly or monthly, you can always make provision for a discretionary income, so that you can invest in Bitcoin because their are so many unnecessary things we spend money on, so if you have a proper financial management skills, their is no way you cannot invest and be successful in your investment, unless the will and the proper financial management skills is not there to navigate your way in Bitcoin investment.