Donna, If you have not already, go to Amazon and set up an account. You can set it with a cc, so all you have to do in the future is to click and purchase. I very seldom buy my books on the Kindle. I like going to Amazon, so that it is easier to see the cover, and the reviews.
Go to the Kindle store on Amazon, and look for free books. Remember you can set the font to the size that is the easiest to read for you.