Ebay is a huge and profitable business thanks to the way it enables users to buy and sell. Now more than ever before anybody can buy or sell anything. Do you want a Ferrari delivered to your door? No problem, you might be lucky and get one for less then $30.000, do you want a new house? Sure, if nobody offers more you can get one for some bucks.
However when it comes to the moment of pushing the button to buy the advertised item there is always one thing that people will look for: TRUST. Most people are already tired of sending money to someone that will just run away with it, maybe it was even a fake account or some hacked account or someone that hacked that account.
The amount of trust one user has is directly connected to the amount of people that gave him positive feedback and the number of people as well, it's not only the quality that counts here, it's the quantity too. If your feedback falls below 90% people will simply not do any kind of business with you. Period. On the other hand if you have 100% feedback from only some users people won't trust you either because you don't have enough users.
To build trust very quickly you need not only to be a very efficient seller but also a very effective BUYER. Sellers want to deliver their item to you as fast as they can and with little or no drag at all. Search for very cheap items that can be digitally delivered to you such as eBooks. Most of them are very good! I already bought some and I am completely satisfied. If you buy around 10 books you will get 10 positive feedbacks at the cost of around $30 or $40. That's very cheap for the resulting effects. Or you may want to go even further and buy more than 200 eBooks. In this case you would spend round $600 but the amount of feedback you would get would lift your trust to a way where people would almost ever trust you like God. Users with more trust usually get the best buyers and higher bidders because of the confidence they inspire in users.