Listen to sports talk radio on Chicago stations such as WGN 720. Many sports talk radio stations offer regular listener contests in which Cubs tickets are given as prizes. You can also visit WGN 720's website to enter online contests to win Cubs tickets.
Visit sports bars with friends or family members on Cubs game days and watch the team play on the big screen. Many sports bars in and around Chicago air Cubs games, and you don't have to pay a cover charge to get in to watch the game. Theoretically, you should order a drink or some food, but you could get away with just drinking water, provided you're with people who are buying food and drinks.
Go to the area around Wrigley Field, 1060 W. Addison St., and look for groups of fans tailgating prior to and during the game. Though tailgating is most commonly associated with football, baseball fans often gather around the stadium to watch the game on portable televisions, eat and play catch. If you meet up with a few friends, you can probably crash someone's tailgating party for free.