Before exiting the central hall, you should turn to your left and stay inside the airport building. Here there are ATM machines. Taking out some local currency is very important, because the route will be using train and bus. You can buy a train ticket with a credit card, but a bus ticket can be payed for only by cash. There are 2 machines - a red one, from HaPoalim bank, and a green one. The green one takes a bigger service fee. And judging by the short line to the banks cashiers, the cheapest way to get your Shekels is face to face.