There is no greater investment than the one you make in yourself. And there is no greater ROI on Earth than the one you can get from books. I don't care what the price of gold, oil, real estate or pork bellies is today, the return on investment from a single book outstrips them all.
On the shelf behind my desk are a half a dozen books—let's say $150 worth of hardbacks. That handful of books has helped me generate hundreds of millions of dollars in sales. The ROI I have received from them is incalculable—and still growing.
I was fortunate enough to receive a formal education. The price of a college degree is staggering, but the return on your investment isn't the diploma but the time you spent reading books and discussing big ideas with a group of smart people. It's expensive, but you can and will get your money back and then some.
Now, whenever I want to learn something, I find a coach with the skills and the track record to bend the learning curve in my direction. The money I spend on a coach speeds my time to results. A good coach can see what you can't see for yourself and holds you accountable for making changes. The faster acquisition of skills and time to results make coaching very inexpensive. Pay somebody.