No idea about East Germany, but it was top end hardware in Poland around 1989, cheaper and more popular than PCs, and easily obtainable even before the fall of Iron curtain as long as you had the cash. The cost was ~5-10 salaries, C64 was 1-3. PCs were rare and crazy expensive, XT cost almost twice as much as A500. 1989 salary was ~100 DM using black market exchange rate. 1990 was the year Russian occupation of Poland officially ended, salary jumped to 170 DM, owning western money stopped being illegal dissolving currency black market. 1991 salary went up to 300 DM, and so on..

Even pre 1989 CoCom embargo was not enforced on the west crossing for ordinary border traffic. Anyone on business trip could just stuff a computer into his car trunk, or a couple with appropriate bribes ready for east border guards.