Start with chu-hai
Chu-hai is a popular alcoholic drink made with the potato based shochu. It is sold in cans and ranges in price from under 100 yen to around 300 yen for 350ml. The price depends on the quality and where you buy it as supermarkets will obviously be cheaper that convenience stores and vending machines.
Popular flavors include grapefruit, lemon, apricot and lime. The alcohol percentage varies from 3-9%