Gulet boat day-trip prices are cheap - £5-10 a head and children often half-price.
Unfortunately, (in my case anyway) the bar bill isn't so cheap. Prices for drinks are understandably inflated on board and this is where they make the money. I think about £2/6 TL (last year's rate) for a 33cl Efes.
Really, just about the best way to exchange money is to withdraw from an ATM using a Halifax Clarity credit card (or a similar card like Nationwide above). No withdrawal fees and "perfect" exchange rate which is 3.5395 as I speak:
www.xe.comYou do accrue interest immediately upon withdrawal, but this is a pittance if you repay quickly. You can do this using your bank's smartphone app to pay your credit card a day or two after withdrawal.
http://www.moneysavingexpert.com/travel/cheap-travel-money#halifax