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From 1964 until 1973, $6.417 billion (equivalent to $33 billion in 2016)[55] in total was appropriated for the R&D and flights of the Saturn V, with the maximum being in 1966 with $1.2 billion (equivalent to $6.95 billion in 2016).[1][55] That same year, NASA received its biggest budget of US$4.5 billion, about 0.5 percent of the gross domestic product (GDP) of the United States at that time.
One of the main reasons for the cancellation of the last three Apollo flights was the cost. In the time frame from 1969 to 1971 the cost of launching a Saturn V Apollo mission was US $185 to $189 million,[1][2] of which $110 million was for the production of the vehicle[3] (equivalent to $566 million in 2016).[55]
I knew... Made a quick TF2 reference...