Disagree on money. There are some aspects of performance marketing that you literally cannot get experience with unless you have a certain level of scale and the spend that gets you there.
If someone wants to seriously go down this path, you can learn a lot on your own, but it can also short circuit your learning to get a job somewhere that has experts you can learn from, and invest in your education that way.
Well, I meant your own money. You certainly need money for certain things, but it doesnt have to be yours. A good performance marketer understands how to leverage somebody elses money to their advantage.
If someone wants to seriously go down this path, you can learn a lot on your own, but it can also short circuit your learning to get a job somewhere that has experts you can learn from, and invest in your education that way.