try ebay singapore. most of those 3rd party battery grips (rokinon, meiki, phottix) can be bought online from hongkong, china or other countries via e-bay but you will need to have paypal and patience since it will take a few weeks for your item to arrive.. i also find buying through ebay cheaper than buying locally particularly those hard to find sony alpha accessories. but bear in mind the risk of buying inline.
so far i have only done small item purchase via e-bay for those hard to find alpha accessories such as;
58mm reverse lens adapter which i got for less than $5
a 3rd party battery for an a500 for $12
a wired shutter release for $4