Are you all changing them in China or taking them in Turkey ?
4 Answers
Local pickup
Cash withdrawal at Turkish airports
It's definitely more cost-effective to withdraw locally.
You can't really exchange money domestically, so you'll have to withdraw cash when you go out. However, you can use cards for meals and tickets, and cash is mainly for buying water and drinks, with an allowance of 50 lira per person per day. 4G is very useful, but international long distance calls are generally not available, and the free calls are for domestic calls in Turkey.