Neisha, to clarify, I have a Barclays connect card & if used in Turkey pay a transaction charge of I think about 1.75%. I have a Barclaycard visa and if used to withdraw cash form an atm I pay both a transaction charge of about 1.75% & I get charged interest from the date of cash withdrawl.
I have a Nationwide debit card and if used in turkey I pay NO charges I withdraw in Lira and it debits my account in £'s at the going exchange rate, in my experience the exchange rate has been at least as good as you get in Turkey.
Hope this helps.