At first this might seem like just one more "commercial" holiday, but rest assured, it is not. Yeah, you gotta go buy a book, but really, in the grand scheme, that's not really a big deal. Between used book stores, discount tables, and the low cost of many ebooks by Indie authors, getting a book won't really break you.
Here's the official statement from http://www.buyabookday.org/:
The National Buy a Book Day Foundation's primary activity is educating the American people on the importance of books to our culture and community by encouraging citizens to go to any bookstore on September 7th of each year, which we hope to establish as National Buy a Book Day, and buy a book. By buying a book, as a community, every year on the same day, we come together in support of books, booksellers, authors, and publishers alike. This is the exclusive goal of the organization, and it is funded entirely from public and corporate donations.
How cool is that?
So, it doesn't matter if you get it online or in a brick and mortar store, just get out there and get a book. Maybe you decide to check out a book by that writer you've been hearing about or discover someone absolutely new. Take your kid to a bookstore as a special treat after school! That's what I'm doing!
As a writer and publisher of my own works, I understand how much effort goes into producing a single book. It's a pain in the butt. I can't imagine trying to juggle the insane amount of books a publishing house puts out. Let's celebrate the wonder of books together, because really, they are magical things that take us to worlds previously undreamed of and allow us to know the thoughts of great men from centuries past.
Go thou forth! Buy a book! Then...maybe...just maybe...read it!