<font color="119911">Hi yaya (laura_yaya)</font>
The "$0.50" coupon is limited to once per batch, i.e. 1 item only.
Total amt (S$): US$4.29 + 3.49 - 0.50) x 0.85 x 1.30 = 8.04
You have excess funds from previous batches, so you do not need to transfer payment for this order. Thanks.