Tourist Bosphorus cruises cost 300+ lira for crowded boats with commentary you can't escape. Bus 25E does the same European coastline route for your regular İstanbulkart fare (17.67 lira) — Starts at Sarıyer in the north, hugs the Bosphorus shore all the way down to Kabataş ferry terminal.

Grab left-side seats heading south for unobstructed water views. The 2-hour full route passes Rumeli Fortress, waterfront mansions in Bebek, and ends at Kabataş where ferries dock. Hop off anywhere that looks interesting — Arnavutköy for seafood restaurants, Ortaköy for the mosque views, or Beşiktaş for the weekend market.

Bus runs every 20-30 minutes from 6am to 11pm daily, dropping to 30-minute intervals after 8pm weekends. Unlike tour boats on fixed schedules, you control the timing. Want to spend an hour photographing Rumeli Fortress? Catch the next bus. Hungry in Bebek? Stop for lunch and continue later.

Only downside: gets crowded with standing room only during rush hours, and you're viewing from bus height rather than water level. But for budget travelers who want Bosphorus scenery without tour boat prices, nothing beats the 25E's bang for lira.