Writers are often victims of scams...but so are the rest of us.
Here's a few things to bear in mind.
1. Never give your credit card number to anyone over the phone if they initiated the call. Even if they say they're your bank or your credit card company.
2. If somebody is trying to charge a fee so you can receive a prize you 'won', then it's probably a scam.
3. If you can't remember entering the contest you just 'won', it's probably a scam. As a tip...if you do enter contests or sweepstakes, make a note of them and what the prizes are. Then you have the quick ability to verify and cross reference whether you really entered or 'registered for' a prize.
4. If the person telling you you just won a prize doesn't know what you entered, either it's a scam or they're not very competent.
5. Be extra wary if the prize is a free cruise, especially if it's a 'free cruise plus resort stay' (A couple of Florida timeshare companies pull this one as an unethical sales tactic). Especially if it's a Carnival cruise...for some reason Carnival is a particularly common company for scammers to pretend to be.
6. If the person saying you won the prize doesn't identify who they work for, then be wary.
7. Buy everything you don't buy face to face using a credit card. That way you can reverse the charges if you don't get the goods. (I would note it is fine to pay cash once you have the item in hand. I've even paid cash for hotel stays overseas...it can be the only option in small guest houses in Europe that might not take credit cards and can only deposit checks in their country's currency...but if you're paying for ANYTHING in advance, use your card.)
8. Don't make a major decision without sleeping on it. This includes accepting what sounds like a really good prize. If they are legitimate, they WILL accept 'I'll call you back tomorrow' and give you a number. Legitimate operators understand that there are scammers out there and will respect you for doing your due diligence.
Just a few tips for today. Hopefully nobody will get 'nailed' any time soon.