Invest in Affordable Rare CoinsWant to broaden your retirement portfolio beyond stocks and bonds? Studies show that the same amount of money invested in the stock market and in rare coins can result in a better return by investing in rare coins. Consider adding rare coins to your investment portfolio. But don't think you have to spend thousands of dollars on a one-of-a-kind coin to see a portfolio return on your investment. For as little as $100 a coin, you can start building a portfolio that can bring solid gains.Learn how great coin collections were built with low-cost coins. See how a portfolio of coins gained in value over 10 years, 20 years, 30 years and more.Study the author's recommendations for affordable coins you can buy now.