Why did the Owl in Harry Potter and the Philosopher's Stone want money, and why don't other birds demand money too?

Question

Very closely related (but not identical): In Harry Potter and The Philosopher's Stone, Hagrid's Owl Wanted Payment. Do Owls Use Wizard Money?

In Harry Potter and The Philosopher's Stone, an owl demanded payment from Hagrid for delivering a message. However, there's no record (that I'm aware of) in the series of any other bird demanding money.

The linked question is about why that particular owl wanted payment. (Actually, I'm wondering the same thing and think that there could be more detailed answers there, but that's a separate question). My question is - why does this only appear in Philosopher's Stone? Sure, Harry's owl wanted food and other rewards, but why don't any other birds demand money - why just that one?

Answer 1

The owl wasn't delivering a message. It was instead delivering a newspaper, the Daily Prophet. The Daily Prophet offers a subscription service that apparently requires you to pay for each copy of the paper daily, rather than paying upfront.

The owl only "demanded" money because it hadn't been paid, and it needed to be. There are other instances in the books of owls delivering copies of the Daily Prophet and being paid (you'll have to take this on faith right now as I don't have access to the books). It seems reasonable to assume that, had they not been paid, they also would have made attempts to obtain payment.

There's another, slightly related, example of an owl "demanding" something from the recipient of a message. At the beginning of Order of the Phoenix Harry sends a message, and tells Hedwig to make sure that the recipient (Ron and/or Hermione, if I recall correctly) responds with actual news about what's been happening. We later find out that Hedwig fulfilled that request.

Answer 2

As Anthony said, the payment is for the subscription of The Daily Prophet. We see this happen a couple times in the books.

‘Hagrid!’ said Harry loudly. ‘There’s an owl –’

‘Pay him,’ Hagrid grunted into the sofa.

‘What?’

‘He wants payin’ fer deliverin’ the paper. Look in the pockets.’

Hagrid’s coat seemed to be made of nothing but pockets – bunches of keys, slug pellets, balls of string, mint humbugs, tea-bags … finally, Harry pulled out a handful of strange-looking coins.

‘Give him five Knuts,’ said Hagrid sleepily.

‘Knuts?’

‘The little bronze ones.’

Harry counted out five little bronze coins and the owl held out its leg so he could put the money into a small leather pouch tied to it.
_{The Philosopher's Stone - Chapter 5: Diagon Alley}

Hermione, however, had to move her orange juice aside quickly to make way for a large damp barn owl bearing a sodden Daily Prophet in its beak.

‘What are you still getting that for?’ said Harry irritably, thinking of Seamus as Hermione placed a Knut in the leather pouch on the owl’s leg and it took off again.
_{The Order of the Phoenix - Chapter 12: Professor Umbridge}

^{(emphasis mine)}

It is not mentioned every time a subscription of The Daily Prophet shows up because it doesn't need to be. Rowling established that you pay a few (between 1 and 5 apparently) Knuts for the subscription, and trusted that the reader would remember that. This information is worldbuilding, but not really integral to the plot, so it's not mentioned every time.

The rest of the time we see owls being used as messengers, it's either Hedwig/Pig whose job is to do whatever Harry/Ron wants. Or it's a school owl that also has to do what they want. The owls themselves could not care less about the money. They just want food and care. So long as they get that, they seem to be willing to ferry mail around.