As everyone says "It was Communism" but by definition communism is a stateless, classless, money less society and if you look at the Soviet Union you know they had all three of them. Even with some forms of socialism means of production was split between state and the people and looking at the Soviet Union it looked like the people had no say whats so ever, there was no democracy in the work force.
Well, it's all dependent on the era you're talking about.
Lenin's NEP (New Economic Policy) after the Russian Civil War was meant to facilitate the transition from feudalism (in Marx's materialist theory, industrialized countries would be the first to have revolutions, he wasn't right in this aspect) to socialism, but the problem for after the Russian Civil War was mostly recovering from it, as well as a lack of capitalist "bridge" before socialism. War Communism worked during the war, according to Lenin, but more permanent changes would have to be made.
With his passing, Stalin's Five Year Plans ushered in a command economy. Basically, the Plans consisted of these stages. -First one was centered around collectivization of agriculture, often forced resettlement of citizens. (1928-1932) -Second one was centered around industrialization. Interestingly enough, lots of American companies were contracted by the USSR. They accepted because there's no money to be made stateside at this point. (1933-1937) -Third one was largely a continuation of the second Five Year Plan. Stalin basically doubled production in order to catch up with the Great Powers. (1938-1941, cut short because of WWII)
After Stalin's death and up to the late 1970s, it was a series of Five Year Plans. Sentiments about a command, centralized economy changed after the Era of Stagnation. Gorbachev was brought in, perestroika was set into place in the mid 1980s, moving further and further towards a free market until the dissolution of the USSR in 1991.
Edit: Just a disclaimer that I'm not a historian, just a Marxist-Leninist.