My late godfather used to buy these SATA greeting seals in the past. Somehow I managed to have a couple of such booklets – from $2 per booklet (10 sheets of 10 seals per sheet) in 1969 to $5 per booklet in 1971. $2 or $5 may not be a large amount now, but at that time (60s and 70s) it was quite a considerable amount.
These are not meant to replace the usual postage stamps but used to decorate your letters as shown below.
For those that do not know what SATA is (click on the link in the first para) , I’m not surprised as TB (Tuberculosis) is no longer a major killer in Singapore. It was in the 60s, thus Singapore Anti-Tuberculosis Association (SATA) was setup in 1947.