You love buying on eBay and Craigslist and pride yourself as being the deal-finder out of your circle of friends. One day, you get an official-looking email, which seems to be from a website's Buyer's Protection Plan. They inform you the seller in your latest transaction was an online crook--and isn't going to send you the goods.

To straighten the mess out, they ask you to provide your account or credit card number to give you back your money. Of course you probably know by now, they won't give you back your money at all; it was all just a ruse to get your banking information.

How to avoid: eBay or Craigslist reps will never ask you to give them your banking information. If they needed to, they could credit the money back to the method of payment you used in the transaction.