In the U.S. the first ounce for letters was 29 cents (23 cents for each additional ounce)and postcards were 19 cents.
For flat paper items, postage goes by weight, not by size.
The 19th G7 summit was held in Tokyo, Japan from July 7-9, 1993.
The postage is standard first class 1 ounce (a "Forever" stamp).
July being 7 it is VII-XXVI-MCMXCIII
It would help to know from which country and to which country.
Go to the site below and click on the "Calculate Postage" tab.
Late Show with David Letterman - 1993 16-169 was released on: USA: 7 July 2009 USA: 7 July 2009 Sweden: 14 July 2009
The Vanishing - 1993 was released on: USA: 5 February 1993 Argentina: 6 May 1993 Australia: 13 May 1993 Ireland: 11 June 1993 South Korea: 11 June 1993 UK: 11 June 1993 Germany: 1 July 1993 France: 7 July 1993 Portugal: 16 July 1993 Sweden: 16 July 1993 Denmark: 30 July 1993 Hungary: 20 August 1993 Spain: 27 August 1993 Brazil: 3 September 1993 Netherlands: 14 October 1993 Japan: 27 November 1993
Beavis and Butt-Head - 1993 Friday Night 2-7 was released on: USA: 14 July 1993
Family Dog - 1993 Dog Days of Summer 1-7 was released on: USA: 21 July 1993
Gabby Chaves was born on July 7, 1993, in Columbia.
It became 34 cents on 7 January 2001.