Let's try to get some perspective, lining the pocket of the companies lead the companies staying in business, authors have more time to write books, keeping the mum and pop bookstores alive. Yes more people keep their jobs thus pump back more money into the economy.
With better profits more bookstores will open thus leading to higher employment.
Now since you want to pay less and it only benefit Amazon because they are the cheapest, you only keep them in business and their predatory pricing kill off the mum and pop bookstores in the mean time leading to higher employment.
The choice is yours to make I have made mine. I pay for my stuffs to keep the people who matter in business.
One more thing pay 2 bucks more is not going to impoverish me if it has so many benefits.