Whoever started this
platitude failed to mention that the worst things in life are
free, too. Breaking up with your SO is just as free as
hooking up with them.
A more accurate restatment would be something like the most exciting things in life are free (or cheap). Because your basic pre-packaged pleasures are pretty much guaranteed to help you hit a nice bland plateau of happiness. The things you find yourself not only tend to cost less, but are also a gamble on increased happiness with only somewhat better than Vegas odds.
I'm a bettin' man; are you?