It is indeed a collectors item. Collectors and non-collectors alike are buying the stamps to remind them of Cory, the greatest president the country has produced.
For those who haven't got the stamps yet, don't despair. My friend said that Philpost will be reprinting more of the stamps.
Update: The reprints are slightly different from the first Cory se-tenant stamps issued by Philpost on September 8, 2009. I was informed that the new Cory stamps were released on September 18, 2009. Word is, the second printing will be as popular as the first and it will also be sold out at once.