During WW2 the Soviet Union supplied the US with certain raw materials and products. The scheme for this supply was "Reverse Lend-Lease". The Soviet Union was able to pay back by providing what the US might need. The list below shows the deliveries.
Chromium ore (tons): 300.000
Manganese ore (tons): 32.000
Petroleum (tons): 1.070
Fruit (tons): 6
Vegetables (tons): 102
Meat (tons): 23
Eggs (doz.): 17.643
Railroad freight (ton-miles, est.): 9.538.050
Railroad passenger (passenger-miles, est.): 1.345.560
Truck freight (ton miles): 60.000
Labor ($): 280.000
Aggregate value (U.S. wartime est.): $ 2.200.000
* Negligible quantities
Source: "History of the U.S. Military Mission to Moscow," Modern Military Records Division, R.G. 165, Box 146, OPD 336TS, N.A., 356-57; Oleg Rzheshevsky, World War II; Myths and the Realities (Moscow: Progress Publishers, 1984), 190.
Feeding the Bear: American Aid to the Soviet Union, 1941-1945, by Hubert P. Van Tuyll. Westport, Connecticut: Greenwood Press, Inc. 1989
I haven't been able to find details on the negotiations and how it was agreed. The food, petroleum and freight is likely to be included because of US troops/personnel being based in the Soviet Union. Chrome ore and manganese deliveries are more interesting. In the link below it is possible to find the US production during the war. The % of manganese supplied by the USSR is not very significant when compared to the local output (~3%), but chromium is more significant. Local output reduces by a quarter in 1944 (145.600 vs 45.600 tons) and reduces to a trickle in 1945 (14.000).
Finally, what does the "aggregate value" include? I can't get how all those items are worth just $ 2.200.000.