Businesses offer freebies in Turkish currency campaign.

What does a country do if its currency suddenly plunges in value?

Some governments raise interest rates, others try to increase exports.

Turkey is attempting a different way, with President Recep Tayyip Erdogan calling on his loyal followers to exchange US dollars for Turkish lira to shore up the faltering currency.

Many are heeding his call – and businesses are offering unusual incentives to take part. Our Turkey correspondent Mark Lowen reports.