The official exchange rate between the two marks is 1: 1, but storekeepers and the black market operators will gladly give you three East German marks for one from the West.
若廿五馬克不夠花也沒關係，一塊錢西德馬克在東柏林的「黑市」價格是三塊錢東德馬克，以西德馬克付帳，最受歡迎。驗過關、換過錢，不過推了三道門，就到了東柏林境內，這是全世界民主與極權間最近的一條通路。