Not just the domain of your nanna and nostalgic collectors, many Australians still use stamps.

On April 3 this year, the price of an ordinary small letter stamp went up 30 cents to $1.50.

Australian online collectibles trader David likes adding the personal touch of custom-made stamps bearing his company logo.

But he got a shock when the 2000 custom-made stamps he ordered came without the actual dollar sign printed on them.

David, who spoke with 9 News, said he didn’t even notice the misprint at first and started sending them out.

But Australia Post emailed him, saying the missing dollar sign made the stamps invalid, an oversight David found “kind of hilarious”.

“I was waiting eagerly for them to come up with the new pricing, and then I ordered them the next day,” David said.

“They had one job, to change the two to a five, and they messed it up,” he said.

“You would think that after so many years of having these stamps that there would be quality control and yet this slipped through for almost a month – it’s kind of crazy.

“Everyone makes mistakes but it’s a bit embarrassing for them.”

Australia Post told 9 News a printing error was to blame.

“A printing error resulted in a small number of personalised stamps being misprinted,” an Australia Post spokesperson said.

The postal agency has apologised and provided refunds, but a stamp without a dollar sign is non-compliant.