Not the Soviet Union, but still the Eastern Block: there was a Lego clone called Pebe and was made in the GDR. This link is Hungarian, sorry, but this page is all about old Eastern Block toys and other stuffs, and the linked subpage is dedicated to the Pebe: PEBE építőjáték | retronom.hu. read more
There were some LEGO clones manufactured in Warsaw block countries that were somehow exported to USSR. read more
The fifty something years I lived in the Soviet Union, every year the government would decrease the price of goods and keep it low for a month. The reason for that would be because that month, the business would introduce more things and newer products and people would buy them for that year. read more