The guided tour was $10 for 1.5hr, not free. Good idea, heard about tour, live in Philly. Wanted to learn more/ see more of city hall. The tour started in a classroom type office with the guide talking for about 20 minutes. Mostly about random William Penn history and city history. Saw a few neat rooms, stairways, sculptures, nice views. Tour ends with the tower, you take elevator to the top just under William Penn's feet. You can walk out and look around in all directions. Great view to say the least. I thought the tour was too long, could of been done in 45 minutes. Glad I checked it out. If I go back I will just pay $5 to check out the tower. Go on a fair weather day as the tour is outdoor and indoor.
Pros: get to see the inside of city hall and tower
Cons: not free, $10 for 1.5hr tour, $5 for tower only