Those tourist boats charging 300+ lira for Bosphorus tours are highway robbery. The IDO public ferry from Eminönü to Anadolu Kavağı covers the exact same route for 90 lira round trip, takes you further north than most tours, and gives you 2+ hours to explore at the destination instead of rushing back.

The ferry terminal at Eminönü is right behind the Spice Bazaar - look for the IDO signs with blue and white logos. Ferries depart multiple times daily (check IDO's schedule for exact times), and the 2-hour journey up the full Bosphorus beats any cramped tourist boat. You'll see both European and Asian shores, Ottoman palaces, the Bosphorus bridges, and fishing villages most tours skip.

Anadolu Kavağı itself is worth the trip - climb 15 minutes uphill to Yoros Castle (14th century Byzantine ruins) for Black Sea views with maybe 10 other people total. The village has excellent seafood restaurants like Balıkçı Sabahattin where fishermen sell their morning catch directly to the kitchen.

Pro tip: While bus 25E gives you coastal views, ferries offer water perspectives and avoid traffic completely. Sit on the right side heading north for the best palace views, left side for Asian shore villages.