First of all you don't need any money to plan investment you think you don't have money now but you will definitely have money in future and then you can invest in Bitcoin for long term. Even if you don't have money now, you can try to get an idea about investing now. You try to get an idea in advance about how strong you need to be mentally or how much financial risk you have to take when investing in long-term plans.
Investing will be much easier for you when you know about such things in advance when it comes to keeping your investment for a long time.
People plan about something when they have money to accomplish it. Before building a house when we have enough money to build a house but we plan how to build a house but if we don't have enough money but it is our dream that one day we will build a house. Planning about something and getting ideas about something are two different things. An investor will plan to invest only when he has money to invest. If he doesn't have money to invest, if he dreams of investing then he can get idea about investment which will help him in later investment. The more a person knows about any subject, the more it benefits him because there is no end to knowledge, the more people know, the more people will master that subject.
As you said that you don't have enough money to invest and the amount of money you have is for running your family but I will tell you that you need to accumulate a lot of money to invest but not talking. You can start investing in your long-term plans with the money left over from household expenses. You may think that investing a small amount of money can be profitable, but when you invest this small amount for a long time, your idea will change.
It can definitely be a good idea for new investors. You have made it easy for the new investor where a new investor thinks he needs to manage enough money to invest. Here you have explained well how a new investor should start investing. If an investor is able to initiate the investment, then investing later on will act as a responsibility for him. Just as he considers it his responsibility to manage the family, once he starts investing, he also considers it his responsibility to consistently increase his investment. Nothing should be done in a hurry, it is better to do it slowly.
From the way you describe your finances, I assume you have at least $10 left over at the end of the month after family expenses, which is enough to invest. If minimum 10 dollars can be invested regularly then after five to seven years your total investment amount will be much higher and I believe when you start investing you will not invest 10 dollars every month but you can invest more amount then.
People's financial condition is not always the same, maybe your financial condition may be bad now but your financial condition will be better in future so start investing from now and keep doing consistently when you have more money you can increase your investment amount.
For those who earn relatively more money, $10 to $20 may not matter, but if those who work in a tea shop are asked about their need for $10 to $20 at the end of the month, they can very well say that they need $10 to $20 at the end of the month. A tea vendor on the sidewalk sells tea to 10 to 20 people and earns one dollar, it would be wrong to say that he earns one dollar because he sells tea for one dollar and here he has some expenses and a small amount of profit apart from the expenses. If a person who sells tea on the sidewalk is asked to invest $10 to $20 at the end of the month, then this $10 to $20 will be the highest investment for him and he will make this investment with great hope.
What I feel is that no action is small and no amount to invest is small with any amount an investor can start his investment.