The title pretty much sums it up. The sources i've come across all speak of "aid" but doesn't specify if that means free money or if the aided are expected to repay any of it. The USA and especially Sovjet giving away lots of money for free sounds weird.
Thanks
The Marshall plan gave aid to 16 European Nations in the four years from 1947-1951. The aid was just under $13bn. (circa $130bn in today's money.)
Most of this aid was in the form of outright gifts of money from the USA to the European countries, but about 10% ($1.2bn) was in the form of loans.
Besides money, technical assistance was another part of the Marshall plan aid.
The Marshall Plan was offered to the Soviet Union and Eastern European Countries, as well as Western European Countries, but they rejected it.
The European Countries were heavily involved in planning the details of the Marshall Plan and how the money should be spent or invested.
Many European Countries co-ordinated some of their own money with the Marshall Plan. Germany, for example, created a system of loans to help businesses rebuild, which worked with Marshall Plan money, but was supported by German funding.
By the end of the Marshall Plan in 1951, all 16 participating countries had seen their economies recover to better than pre-WWII levels. The aggregate GDP of the 16 countries was 35% above what it had been in 1938.
Source: http://www.marshallfoundation.org/TheMarshallPlan.htm