I think few of foreign visitors to Japan have taken advantage of "Starbucks One More Coffee." They sell the second cup of drip coffee at a very low price. It is 100 yen+ tax (108 yen in total now).

How to order:
Show the receipt of your first purchase on the same day. Your first and second order must be of drip coffee. Your options are....

same or smaller number of cups are allowed
same or smaller size only
at the same shop <-> a different shop
hot<->ice
regular<-> decaf
any brand within hot, ice, or decaf

There may be some FTers who think they have spent thousands of yen for nothing.