The best and cheapest Japanese food store that I have found in Melbourne, Australia is called the Hong Kong Supermarket. The Hong Kong Supermarket located at 367 Clayton Road, Clayton VIC 3168 has a big range of Japanese food products as well as the usual Asian food products from China, Korea, etc. We usually buy our Japanese staples there such as soy sauce, mirin, Japanese sake cooking wine, nori, tofu, age, miso, and furikake (rice seasoning). They also stock a range of Asian snacks and sweets which are real tasty. Please see map below for more details.