Last week, I decided to pay $79 for shipping on cotton pads — and this may be one of the smarter financial moves I've made recently. Sounds crazy, but let me explain. Amazon.com has a program called Amazon Prime, and the annual $79 fee covers free two-day shipping on millions of items. Naturally, it covers the beauty department (which has more than 400,000 items!) along with books, snacks, electronics, and the like. Find out why it makes financial sense.