Here in the UK we learnt at school that Britain began repaying the loans back to America almost immediately and obviously continued to do so.
What about Russia though? They benefited massively from American materiel and I'm sure the American government wouldn't just give it away for free.
Basically, what was the situation regarding payment for the materiel sent to Russia given the fact that the Cold War made them enemies of the US? Did they even have to pay? Did they not pay any? Some of it? All of it?
Yes, they had to pay. Part of the materiel was paid for during the war in gold bullion or ore. As per the original agreement, after the war was over the Soviets returned the equipment they had no longer any use for and the Americans wrote them an invoice for $1.3 billion. This was later recalculated at $722 million. The two countries agreed on this sum in 1973 and the USSR started repaying the debt. Payments were halted at some point over the US discriminatory trade restrictions on the USSR. The remainder of the Soviet debt was repackaged after the collapse of the USSR and paid off by Russia in 2006, which seems to be the year Britain paid off the last of its lend-lease debt, too.