Names of tour companies and their itineraries change frequently so it's best just to make arrangements through a travel agency or your hotel; the offerings are all pretty similar. If you join a group, a "classic tour" of the Aya Sofya, Blue Mosque, Hippodrome, and Grand Bazaar should cost about 90 TL for a half day. For a full-day tour that also includes the Topkapı Palace and Süleymaniye Camii, as well as lunch, expect to pay about 180 TL. Bosphorus tours include a cruise and excursions to sights like Rumeli Hisarı and the Dolmabahçe or Beylerbeyi palaces. Rates for private tours with a guide and driver are higher, and more cost-effective if you have a large party; for two people, expect to pay at least 250 TL per person for a full day, and about a third less per person if you have four or more people. Keep in mind that admission fees and meals are generally not included in private tour rates, so this alternative ends up being considerably more costly.