There are billions of people on the planet.
Once we learn to sell, we can convince many of them to give us money, time, attention, and opportunity.
But there's a caveat: selling, alone, isn't enough.
Ethical sales requires a high-quality product. When you break your promises, it hurts you in two ways:
1) Your reputation is weakened.
2) Before long, people will stop buying, and you'll have to build an entirely new product just to stay afloat.
Technically, if your market is large enough, you could burn through billions of people with a bad offer...
But then you'd be a fraud. And no amount of money is worth being a fraud.
In an ideal world, we wouldn't need to sell.
We'd just build cool stuff, and grow through referrals.
So I recommend saving the following concepts for when you already have a great product (yours or an employer's).
In the beginning, this means you miss out on fast money.
But often, fast money now = no money later.