Let's suppose you are in your 20s and want to fully devote your life to something you are highly passionate about, but there's a problem: you are unsure whether that activity will bring you any substantial money in your lifetime. For example, you want to do some research that is difficult to get funded. At any rate, what your desired activity requires is pretty much just a computer and an Internet access, and you can do that from anywhere in the world. Approximately what minimum amount of money do you need as a lump sum deposited to your bank account (e.g., as a result of getting an inheritance or winning in a lottery) to ensure that you can devote your life to that activity and cover your living expenses for the rest of your life?
Some clarifications and constraints:
You are a citizen of a highly developed country like Japan or USA, but do not mind migrating to a different country to cut the cost of living, and you are prepared to learn any foreign language. However, as we know, different countries have different immigration requirements.
You do not have any addictions or expensive hobbies and run a modest lifestyle, but want at least reasonable standards of living:
- a separate unit of reasonable size (e.g., a studio of 30 square meters or so), owned by you or leased to you, with electricity, shower, hot and cold water supply, a washing machine, sunlight, and practically unlimited Internet access,
- safety (i.e., crime rates small enough not to substantially affect your life expectancy or cause stress),
- healthy and fulfilling diet, and
- acceptable ecological environment (i.e., one that won't substantially decrease your life expectancy).
You do not want to work in any way, even by running a small farm to feed yourself or by physically building your home. You are prepared only to do shopping and household chores like cleaning, washing, ironing, and cooking.
You can invest in anything and buy whatever you can buy with your money, but you do not want to regularly spend a substantial fraction of your time managing your investments.
Your plan must also address your future ageing: you should allocate money to getting proper care from a state or a private person.
Let's exclude possible romantic relationships and marriage from consideration, in order to get a reference point. In particular, your plan must not rely on the possibility to solve your financial or immigration issues by marrying anyone.
You do not want to break any law, or, to be more precise, to risk getting jailed, having to pay a huge fine, or otherwise destroying your plan by being caught violating a law.
You are prepared to live only in a sufficiently civilized environment (with effective police, medical care, real estate market, etc.), where you do not need to develop a large network of social connections to get things done and can just rely on yourself, your money, and law enforcement.
If possible, please come up with a concrete estimate in US$ and start your answer with your figure. I am also curious to read at least a brief substantiation (e.g., how to choose the location and invest the money).
UPDATE: There may have been similar questions on this SE, but an important thing about my question is that you can choose any country to live in (provided you can find a way to migrate there). The immigration rules and the cost of living vary widely, and I am curious as to how much you can realistically reduce the cost of living by choosing the location, but without compromising on things outlined above.
UPDATE 2: The question is not intended to be a shopping list question, because the focus is not on which location is the best; I rather want a rough estimate of the amount of money needed. I guess there is a fundamental limit below which you just can't go if you want to lead the lifestyle outlined in my question, and I guess there are quite a few cheap countries that do not require significantly more money than that limit. So my question is basically about what is that limit.