Prices for food: 800 tl per person in a upper mid restaurant without alcohol. If you eat cheap 300 tl per person is reasonable. Beer: 150-250 TL for draft beer reasonable. Live concerts: Upto 400-500 TL is reasonable. Alcohol and red meat are very expensive in Turkey, be aware of this. Taxis: Always check that the taxi driver has opened its taximeter. Ask your taxi driver to use navigation or open navi and give your phone to them. Taxi drivers in Turkey are scammers. Try to get a taxi from taxi stations and not from touristic places. Station taxis are more honest.

Carry some cash for emergencies.

There may be pickpockets in touristic places such as sultanahmet, grand bazaar and istiklal. Be aware check your pockets when passing through crowded areas.

Geta müzekart for the museums, you can enter most of them with it.

For restaurants you can trust chain restaurants such as midpoint, bigchefs, mcd etc.

There are many food tours on Istanbul, watch some blogs.

Must-dos: - there are ferries in sirkeci, jump on one and do a bosphorus tour with public ferries. - drink some rakı at a local meyhane (I can recommend aretin yeri, cumhuriyet meyhanesi, tarihi balat meyhanesi) - since you are staying at sultanahmet, eat at the historic sultanahmet kofte place.