Omaha police say they're seeing an increase in online scams that in some cases cost people thousands of dollars.

Police are asking people to use common sense and don't fall for something that sounds too good to be true.

Some scams target Web sites like Craigslist and eBay. Those behind the scams offer to pay the seller more than requested for an item. They ask the seller to keep some of it and wire most of the extra cash back. The problem is the check or money order sent to the seller is fake.

Scams also are targeting online job search sites including Monster.com.

Police warn such crimes are hard to investigate and sometimes they can do little or nothing for the victim.