The design of the pre-printed image was to promote support for South Africa's Bid to host the 2010 Soccer World Cup. These stamps were dubbed "Virtual Stamps" by the Post Office, were put on sale as a trial commencing on 5th February, 2004 at only Four counters, one at each of the post offices of Bryanston, Menlyn Central, Kempton Park, and Johannesburg International Airport. These are all in the province of Gauteng, and the stamps were not on sale anywhere else. The intention was to have the postal item weighed, and the required value printed on each stamp according to the prescribed rates for the weight and service required. This was calculated automatically by a scale-linked computer at the counter, also linked to a thermal printer.These stamps were never sold from any form of Vending Machine!
The roll of blanks as supplied to the four issuing offices: 
Stamps of requested denominations were also sold across the counter. Any Face value from 1Cent to R5000 could be ordered. The writer knows of mint and used copies with a R100.00 face value.
The trial continued until +/- July, or when the individual offices' supply of blanks ran out. The 28th Edition of the South African Colour Catalogue was being compiled for printing during the period of sale, and the editor had no idea that the sale would stop abruptly, thus the retail values assumed the stamps would be readily available. The stamps were used for Parcels, normal and registered local and international mail.
Unused stamps which bear the barcode and value are relatively scarce, especially in pairs or vertical strips of three or more. Most values seen have been separated vertically by scissor cut for display as singles. Quantities existing unused for most values are very low, often less than 30 copies recorded, many even less, hence the high prices realised at auction. Possible exceptions are Standard Postage, sold most often, and Blank stamps, which reportedly exist in rolls in private hands.
The blank stamp being sold here was reported as being obtained over the counter as part of a strip of stamps with face value. Proving pieces of such occurrences exist- ie. blank in pair with normal value printed stamp.
A strip of 3 x 20c values realized R2600+premium at the April 2007.Sotheby's Auction in Rosebank. Unused singles of other value-printed examples have recently realised between R400 and R1750! A used example on cover to Australia recently realised R1980 on BidorBuy.
