Presidential Cups

Submitted by Harlene:
Greetings!
I have 4 white/cream colored hard plastic cups with the seal of the President of The United States on one and the seal of The Vice President of the United States on the three others. I have been told they are from the 1970's. I purchased them at an estate sale near Vandenberg Air Force Base in California. I would interested to know their value?

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