Just a short note, please remember that although you are honest, you will find that a lot of people out there are not!
If you are buying, look for positive feedbacks, look at what other people have said. If someone has a high rating, do not presume they are an angel. To get a rating you can buy or sell, some unscrupliuous people will sell a load of cheap tatt or e-books or whatever at low prices to get a good rating then start selling fraudulently and you will lose out!
Check what sellers ratings were for, if they are for completeley different items, be a bit cautious, look at other sales of similar items to what you want, if something seems too cheap, there may be a problem!
Remember, the law of 'caveat emptor' or BUYER BEWARE sometimes if you have not read the details properly, you are legally bound to buy a piece if cr*p and as long as it can be proved that is is not misleading, you have no comeback!
At the end of the day, e-bay is always going to be a risk, just make sure you take precautions to ensure that nobody takes the p*ss out of you, try to deal with people who have proven reliable.