You’ve identified self correctly @bubblebobble, as you seem to live within a bubble IMHO. I guess it is time for you to come out of it and start living life with an attitude of gratitude to one and all. Now is the opportune time for making it a habit to express thankfulness and appreciation in all parts of your life, on a regular basis, for both the big and small things alike. Just look around you at the built environment, towards everything and anything that you make use of for your existence. They are all there for your convenience and existence because of someone else’s contribution to society. Then you will understand the positive side of selfishness. This is what one of my beloved authors had to say on it:
The Objectivist ethics proudly advocates and upholds rational selfishness—which means: the values required for man’s survival qua man—which means: the values required for human survival—not the values produced by the desires, the emotions, the “aspirations,” the feelings, the whims or the needs of irrational brutes, who have never outgrown the primordial practice of human sacrifices, have never discovered an industrial society and can conceive of no self-interest but that of grabbing the loot of the moment.
The Objectivist ethics holds that human good does not require human sacrifices and cannot be achieved by the sacrifice of anyone to anyone. It holds that the rational interests of men do not clash—that there is no conflict of interests among men who do not desire the unearned, who do not make sacrifices nor accept them, who deal with one another as traders, giving value for value.
If you have the time please read her three novels… Atlas Shrugged, We the Living, and The Fountainhead by Ayn Rand. Now I will try to stay within the limits of Dhamma of the Buddha in answering your question “How can we earn money while we don't want to live for anything?” with the hope that it will help you to go further in this Noble Path. Firstly let us rephrase the question: ”How to live with the least money possible?
Not knowing your temperament, I’m a bit hesitant in writing this. Anyway, here goes…. When Buddha instructed his own son Rahula on the practice of anapanasati meditation, the Blessed One recognized Venerable Rahula’s temperament and what would be most suitable for him. As temperaments differ, so do the objects of meditation, and Rahula was advised to practice other forms of meditation before Anapanasati. So I am not sure whether you are ready for what I tell you or not.
I see that at present you are not a person without any means of support. You are not a destitute person. But there will come a time to live meagrely, if you are serious about this Dhamma path. It will not be an issue if you become an ordained monk, as then you will be free. The question is if you wish to remain a lay disciple, as then you may not be free from all expenses. All what you can do is to just make it significantly lower.
Before starting on the Dhamma path these are the thing that you may have to do. As you do not want to live for anything, start doing the following: a] stop eating out; b] cut out technology (Netflix, games etc.); c] cut down on processed foods, eat healthy, cook at home; d] Wear the clothes that you have for decades until they fail; e] Stop going out for movies and other shows, a walk in the park will do for an outing; f] do not indulge in any luxuries, get used to frugal living; g] save the little extra money that you have for a rainy day; h] go back 50+ years and compare how people lived then (and mind you they were happier then); j] make Gautama Buddha’s Dhamma your hobby & pastime. The liking to this PATH should far outweigh / exceed liking for all other things.
Such a change in you is not possible if you do not limit yourself to reading only the first 57 books on Dhamma ever written, and while at it put into practice what you learn. This first 57 books on Dhamma is your Teacher. So never question the authenticity of these first 57. Then what is called as gift of principle (patipatti dana) will begin to occur from within own self. It is the gift that functions in the cessation from the attachment to the six sense faculties. This gift is nobler than material gifts of food and drinks.
Then you will inevitably to make a commitment to genuine morality. One who practices the True Dhamma will form his mind into prudentially with moral rationality. The one who is being fixed in morality does untie all the tangles, being restrained from within own self. Such a person can walk into a jungle and live there for months without any harm coming to them from animals. Few westerners who come to SriLanka to practice Dhamma do this. The jungle will provide what is necessary for their survival.
I can go on and on and on with many other pointers, but this is a very good start. Once you are well on the way on this new way of life, ask me what to do next. You will not fail, as I’ve tried it, and it had worked for me. Today I’m financially independent. I keep earning money while I don't want to live for anything. (I started with nothing. 30 years ago, at age 24, when I came to Canada with just $200 in hand). You too will live this truth, if you honestly strive for it. Good luck to you.