A special edition Manny Pacquiao stamp is turning thousands of Filipinos into stamp investors.

The Philippine Postal Corp (Philpost) has produced 500,000 stamps featuring the boxing great ahead of his much-anticipated fight with Floyd Mayweather on Saturday.

Manny Pacquiao aims to become the first person to defeat Floyd Mayweather

Almost all are now sold out following their release on April 20 - a testament to the boxer's popularity in his homeland - and the excitement generated by the fight.

And while 500,000 seems like too large a number to offer buyers any hope of a profit, history is on their side.

Philpost's postmaster general, Josefina de la Cruz, explained to the Philippine Daily Inquirer that the 2008 stamps which featured Pacquiao - the first time a living Filipino athlete had appeared on a stamp - are now worth $9.

"If Pacquiao wins on Sunday, can you imagine how its [the 2015 stamp] value will skyrocket?" she said.

"I think that's one of the reasons why people are not settling for just one or two stamps."

"The Pope Francis stamp, which was just P40 (90c) when we released it [earlier in 2015], is now selling on eBay at P500 ($11.20) each," she added.

While at these prices, no one is going to get rich any time soon, the story is testament to the public interest stamps can generate.

Looking for a stamp investment with greater earning potential? Take a look at Paul Fraser Collectibles' stock of rare investment-grade stamps.

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Floyd Mayweather and Manny Pacquiao face off in Las Vegas on Saturday evening, in what is being billed as the Fight of the Century.