The basic tenet of capitalism is that trade is not zero-sum: it actually creates wealth.
If I have I pay you $10 for a service that costs you $5 to provide, you've actually created $5 of wealth out of thin air. I end up with a service that I value more than $10 so I come out ahead, and you end up with money that you value more than the marginal cost of providing me that service so you come out ahead.
As a simple check, the average person (in the world) today is better off than the average person 50, 100, or 1,000 years ago. Even though are population has increased significantly, our wealth has increased even more.
If I have I pay you $10 for a service that costs you $5 to provide, you've actually created $5 of wealth out of thin air. I end up with a service that I value more than $10 so I come out ahead, and you end up with money that you value more than the marginal cost of providing me that service so you come out ahead.
As a simple check, the average person (in the world) today is better off than the average person 50, 100, or 1,000 years ago. Even though are population has increased significantly, our wealth has increased even more.