Notify auction sites of complaints or problems. They want to know about sellers who misrepresent their offers or don't deliver the goods. Get free insurance through the auction sites whenever available. There is usually a small deductible required, but well worth it. Use authentication programs if purchasing stamps, rare coins or some other collectible.
Services are available for grading and verifying products.
Use common sense. And be sure to check out Internet Scambusters to see what the latest Internet scams are out on the world wide web. University Degree Programs - They claim to increase your personal prestige and money earning power through an advanced University Degree. Selling Products - Claims that you can generate hundreds of dollars by sending mass emails or other consumer products. Some unscrupulous companies, claiming to provide free web design and hosting services, are billing small businesses for services that were never authorized and have little value.