The metro system is a good mobility option. As Africa's only metro system, be assured that the metro is comfortable, modern, clean, and safe. The major interchanges are Mubarak (at Midan Ramses) and Sadat (below Midan Tahrir).
If you are a female traveler, the first two carts are reserved for women only, though you can travel in any cart without encountering harassment.
Also, the fare to expect is around 75 piastres for about nine stops.