Gift card schemes are becoming very common these days. You will receive a mail stating that you just won $25 GC or so and to verify that you will have to give personal details to the sender. Some scammers are ready to give you $25 GC for just $10 and so on. The best way to deal with these emails is to delete it right away and also mark them as spam mails. You should never click on the links given on these mails. But there are genuine stores too who give away valid gift cards to their loyal customers. It is really difficult to filter the right ones. If you don't know the sender try to verify it over phone or through other ways before going ahead.