As recently as twenty years ago, if people wanted to publish a book, they would either have to convince a traditional publisher to publish their book, or shell out hundreds or thousands of dollars in order for a self-publisher to print their book for them. Some of these old self-publishing companies still exist - such as Morris Publishing, who, according to their website, charge around $5 a book for a 40-page book with a 25-book minimum. Others, such as the infamous Vantage Press, went out of business a few years ago and were even sued by the authors they were supposed to be supporting in 1990.
Recently I’ve downloaded a game onto my Android phone - Star Trek Timelines. The reason - other than for enjoyment and to occupy my time - is twofold: I want to publish my own Android game at some point, and I need to spend my Google Play credit I’ve earned via Google Opinion Rewards before it expires.