Try one-cup sake.
One-cups are 180ml containers of sake sold in bars, stores, and vending machines in Japan (as well as by mail-order to 18 states in the U.S.). A subculture has evolved around the jars, adorned with illustrations and collected by fans. For novices, one-cups can be a low-risk first step into the world of premium sake (they cost under $10). Try the Akishika "Bambi Cup" – clean, dry, and grassy – and keep the jar as a souvenir.