Not to discourage further discussion, as there is always more to be said, but you may want to check out the AskHistorians FAQ, which has a section on the Soviet Economy and Lend Lease. Lend Lease. Starting in march 1941, Lend Lease, or An Act to Promote the Defense of the United States, was a policy of the United States in which the US supplied food and materials to the Commonwealth Nations, The Republic of China, and the Soviet Union. Although, as u/jorgeportodisz points out here: The UK and Canada contributed much more material to the Eastern Front than the US did.

... also it turns out SPAM became rather popular among the Soviet population as a result of Lend Lease