These top REITs trade at dirt cheap valuations.The stock market has been on a major bull run over the past year, rallying more than 35%, and now stocks are getting more expensive. The S&P 500 currently trades at nearly 25 times earnings, up from about 20 times at this point last year. While bargains are getting harder to find, there are still plenty of deals out there if you know where to look. For example, several real estate investment trusts (REITs) trade at bargain prices right now, including Realty Inc ...