The famous Publishers Clearing House will be awarding its annual prize soon and scammers are taking advantage of this fact by telephoning people to tell them that they have won a huge prize, but they have to purchase a prepaid gift card or prepaid credit card and provide the number to the caller in order to be able to claim the prize. If you do so, you will end up losing the money that you paid for the card to the scammer.
As I have often said, it is hard enough to win a contest that you have entered; it is impossible to enter a contest you have not entered. However, many people do enter the Publishers Clearing House contest so you may find it credible to be contacted by someone purporting to be with Publishers Clearing House to tell you of your lucky day. The fact is that Publishers Clearing House will only notify you by regular mail or in person. They will not contact you by phone or by email and they will never ask for any administrative fees or other costs to be paid to claim your prize.