I received a call from Gift Card Castle approx. 2 weeks ago telling me I won a 100 dollar gift card to Walmart and a 100 dollar gas card. All I had to do was complete an online survey, for a processing fee of $2.99. Upon completion I was told I would receive and email giving me the info for my gift cards. It has never happened.
Obviously this was a scam - at least you weren't taken for more than the $2.99.