It is easy to avoid being scammed depsite what people think, it is common sense. If you feel your vulnerable, oap, young or simply to naive then simply don't deal with people or countries that you feel are more risk. For example, if your a UK user then stick to selling only in the uk rather then worldwide as this will automatically reduce the chances of you being scammed. Also, if something sounds too good to be true then it probally is.
When buying something on ebay, spare a few minutes researching the seller by browsing through the user's feedback, check how long he has been registered, contact other users who may have dealt with this particular person & if in doubt - WALK AWAY!
The golden rule is, trust your judgement & you will stay a winner.
Hope this helps guys & feel free to email me if i can be of any help at any time!