With Samsung's latest smartphone Galaxy Note S4 only days away from release, South Korean wireless service providers are competing to drive new contract sign-ups with a very enticing offer known as "Minus Phones": a free smartphone and instant cash back. According to Yonhap News, smartphone retailers in Seoul are rushing to clear their old inventories in anticipation of a massive device upgrade to Galaxy Note S4, with some locations even offering a cash back of up to ₩50,000 ($45 USD) on top of a free Galaxy Note S3, which has a retail price of $714 USD.