I bought these Brunei 1910 $25 stamps about seven or eight years ago. They cost me about $1,600 (M$4,000) then. Today, according to Steven Tan in his famous International Stamp Catalog for Malaysia, Singapore and Brunei stamps, each of the stamp is now worth M$2,600 making this set worth $4,160 or M$10,400 and more as the stamps are in a block of four. Not bad. The value has gone up two and a half times. Who says stamp collecting does not pay?