TANGS The Wonderful World of Mooncakes. TANGS is now offering the Mooncakes festive with the best brands in Singapore. With Discount Up to 20% off for Citibank and TANGS Cardmembers and a $100 nett spend will earn you a free limited edition wooden tissue box holder. While stocks last.! Come over to the Vivocity to sample number of selection of mooncakes flavor.