"I just looked at it and I said 'what the heck?'."
The Highlands Intermediate School student said he didn't consider pocketing the dosh as "that would have been rude".
"He was travelling here from Australia or something and that was his holiday money."
"He would have been stuck in another country without his wallet, which wouldn't be good."
Sam enlisted his policeman dad Bruce's helpbut the pair were not unsuccessful in tracking the man down.
Bruce logged the wallet at the police station as a found item and the owner, who was visiting from Australia, turned up soon after to claim it.
Delighted to have his wallet returned, contents intact, the Aussie handed Bruce a $100 note to pass on to his son.
Sam was surprised at the reward.
"I just think he's the nicest guy and i don't deserve that, just for handing in his wallet."
Sam said he didn't have any plans for the money, but his mother, Michelle, suggested he might put it towards a pair of new basketball boots.
Michelle said Sam's honest wasn't out of character.
"That's just Sam - the first thing he did was come back and ring Dad straight away - he had to get it right."
Sam said he hoped that anyone else would do the same thing for him.