I already made a massive effort post about this so there is no thread to really be had.
Please read https://www.nationstates.net/page=dispatch/id=921020
TL;DR: Lend Lease was barely 4-10% of the Soviet war-effort, and the majority of it was delivered after the Battle of Stalingrad. The first deliveries didn't reach the USSR before the Battle of Moscow halted the German assault and pushed them back.
On top of that the majority of Lend Lease tanks and planes were inferior to both Soviet and German tech used, only the Studebaker truck and Aircobra were worth a damn.
On top of that was the fact that the main reason the Nazis had the power to even begin the war was because American, British and Continental European corporations actively supported Hitler up until 1941, with Rockafeller's Standard Oil helping refuel German Submarines up until mid 1942.
>inb4 Muh 1939-1940 Soviet-German trade pact
Soviet exports to Germany were 5th place in terms of amount and were only even that high because they got embargoed from their usual sources. The amount of Wheat the Germans got in trade from the USSR wasn't worth even a month of bread for the army and was less than 1% of Soviet food stocks. The USSR received thousands of pieces of machinery, equipment and military vehicles including a semicomplete ship of the line, the Lutzow, which took part in the war against the Germans.
The Nazis were also politically supported by the West throughout much of the war and prior to it, with Poland being a major part of this.