You have many more options to produce your book now than even just three years ago. It used to be that your only choice was to invest thousands of dollars in printing thousands of books all at once in order to get the per-book cost down to a reasonable level. Not any more.
You can still do a big print run if you think you’ll sell through your garageful of books before your house falls down from old age. It’s still the best way for writers to make the largest net profit from book sales, as many authors and organizations do with moderate to great success.
However, other people prefer to use print-on-demand (POD) services. While the cost per book is higher, books can be printed one at a time, which lowers the upfront risk of producing a book to almost nothing. This emerging technology is what made the old way of publishing start to crumble.
The third way to produce a book is to prepare it for electronic books (ebooks). This technology is of course changing the whole publishing world. Other than the cost of formatting your book for epub or kindle, there are no physical copies to purchase and then store.
The path you’ll choose depends on how much you’re willing to invest and how many books you think you can sell, and whether you want just one mode of production or a combination of print and ebooks. In the end, how many copies you can sell is directly tied to how easy it is for your readers to buy your book…which is tied to distribution. And in the realm of self-publishing, you have to consider both production and distribution at the same time.