Many of Philadelphia's historical attractions are free, including Independence Hall, the Liberty Bell, Christ Church, Elfreth's Alley, Franklin Court, and the Edgar Allen Poe House. The U.S. Mint is also free.
Check out this listing of the best free summer activities in Philadelphia, compiled by the tourist board http://www.gophila.com/C/Things_to_Do...
Other free activities include:
First Sunday of the Month: Pay as you Wish at the Philadelphia Museum of Art www.philamuseum.org
Sundays Only: During summer, The National Liberty Museum www.libertymuseum.org is offering free Sunday admission. This small museum, located near Independence Hall, celebrates the concepts of freedom, diversity and nonviolence, and displays some interesting glass sculptures.
Free Self-Guided Walking Tours http://www.theconstitutional.com/tour...
Free Pod-Cast Tours http://www.gophila.com/soundabout/
Free Festivals at Penns Landing http://www.delawareriverwaterfrontcor...
First Fridays Every First Friday of the month from 5-9pm, it's free to roam the many art galleries in Olde City is a fun way to hang out with friends and socialize, and the best part , its all within walking distance to many restaurants and bars to relax after roaming the galleries.
The Settlement Music House 416 Queen Street in Philadelphia http://www.smsmusic.org/calendar/inde... has a great calendar of free music concerts. What's terrific about the school, too, is the thousands of students who are assisted financially by the school. The best and brightest of the young musicians can find their way to the Philadelphia Orchestra by sheer talent alone. This is worth a listen to the professionals who play at the school, for free, as a donation to the community. Concerts include events such as "An Intimate Evening of Music for Cello and Piano," as a typical type of event.