West Germany wanted to buy the East from USSR

“The American files show that chancellor Ludwig Erhard, despite being credited as one of the men behind West Germany's post-war economic miracle, was prepared to hand over a huge sum of money to Moscow for the prize of reunification.

A document seen by the German news magazine Der Spiegel records a conversation between a German government official and George McGhee, the US ambassador to Bonn, in October 1963. The American was told Germany was prepared to pay over $2 billion a year for a decade to Moscow in return for East Germany: a sum which then amounted to about a quarter of West Germany's GDP.”