On April 30th, the US Post Office released the "Stamps to the Rescue" to raise awareness of the need to adopt pets from animal shelters. I bought my stamps when they first came out.
Today I inquired at the post office about buying more of these stamps, and the clerk told me that they had sold out of them within about five days!
This is great news that so many people are interested in spreading the word about adopting shelter pets!
My branch of the post office expects to have the stamps back in stock in a day or so.