Free transportation. The ubiquitous tourist trolleys do a good job for about $25 a ticket. Through Sept. 5, though, vehicles marked ''Free Trolley" will get you to the Navy Pier entertainment district, the North Michigan Avenue shopping district, Adler Planetarium, Shedd Aquarium, Sears Tower, Museum of Contemporary Art, and many other spots. Most trolleys run 10 a.m.-6 p.m. daily; the Navy Pier trolley goes during pier operating hours. Weekends and holidays, a shuttle bus goes to Lincoln Park or Chinatown. Visit www.cityofchicago.org/transportation/trolleys.
Free tour. Chicago Greeter matches you up with a trusted local ''expert" to experience a particular Chicago subject or neighborhood in a two- to four-hour tour on foot and with public transportation. Register at least seven business days in advance at www.chicagogreeter.com.
Free museums. If you're there at the right time, admission is waived at these places: Monday, Chicago Historical Society; Tuesday, Art Institute of Chicago, Museum of Contemporary Art (5-8 p.m.); Wednesday, the historic Clark and Glessner houses; Thursday, Chicago Children's Museum (5-8 p.m.), the Notebaert Nature Museum; Friday, Spertus Museum, which examines Jewish culture (1-3 p.m.); Sunday, DuSable Museum of African American History (noon-5 p.m.). These places, on the other hand, are always free: ArchiCenter, Chicago Cultural Center, City Gallery at the Historic Water Tower, Jane Addams Hull-House Museum, Museum of Contemporary Photographs, Oriental Museum, and Smith Museum of Stained Glass Windows.