As the old joke from behind the Iron Curtain said...

Q: "What would happen in Saudi Arabia if Communism triumphed there?"

A: "First, shortage of oil, later, shortage of sand."

Edit: for all the downvoters, shortages were our daily lived experience when I was a kid. I still remember chasing such rare stuff as "kid's sneakers" or "toilet paper".

And Czechoslovakia was still better off than neighbouring Poland, where you could walk into a shop and find literally nothing in the shelves.

The black market was the only thing that reliably worked.