focus on International market like ebay-us or uk. ebay SIN should take it as a side-dish instead. for the market there is very attractive if you do it the right way.
for those generating more than 500SGD on a sole-profitor, maybe you would consider the ebay store that they offer. To make ur website attractive, maybe conveniency comes in, like paying method & some attractive offers.
The only - point for ebay-UK is the setup price. More risky. The best way You can do to market big is to find distributor or regular bulk purchasers on ur site.