So the the entire cost can be paid with 6759 Panzer IIIs not built to make products the Soviet Union wants.
In 1943 the Germans produced 11601 tanks, presumably mostly lost in wastage on the eastern front. So Germany can easily pay for the plethora of economic good received under the agreement (see table), far more than she received by invading and looting the place
So if the German and Soviets maintain the peace and maintain their economic relations at this level does Germany have the economic resources to fight off an eventual USA/British invasion of France.
Presumably the industrial metals would allow the Germans to build have quality jet engines, stronger armor on tanks, more oil resources allows for a higher level of Luftwaffe training, etc....