Do you have to pay to attend Hogwarts?
In Sorcerer's Stone, Vernon Dursley tells Hagrid "I AM NOT PAYING FOR SOME CRACKPOT OLD FOOL TO TEACH HIM MAGIC TRICKS!" This, and other instances, (particularly in Sorcerer's Stone,) lead me to believe that it costs money to attend. But the Weasleys put six kids through Hogwarts, and they were a poor family. They probably wouldn't have managed if it cost money to attend. Please help!
I don't think that you have to pay to attend Hogwarts - I believe that Uncle Vernon was under the impression was like a Muggle Private School which required payment. However, people like Lucius Malfoy seem to have given large donations. I think that the school runs on money from the Ministry and large donations from families of attendees that have the money to spare.
I dont think that you would have to pay to go there, but I would imagine that a wand, all the books, ingredients for potions and optional brooms and such would cost a hefty galleon. So, it was probably that uncle Vernon was clueless or he was just talking about the cost of books and uniforms.
Hope that helped.
I actually tend to think there would be tuition. It's a boarding school, after all--where else would they find the money for teacher salaries, supplies, etc.? I don't think private donations can cover that. Also, Harry in PS says something along the lines of 'I haven't got any money', to which Hagrid responds 'D'ya think your parents left you nothin'?' and mentions Gringotts. As to the Weasleys...I imagine they make do somehow. Maybe they're dirt poor due to tuition. After all, many ordinary expenses they can cover with magic. So school supplies and tuition might be where Arthur's paycheck goes. (Food can be duplicated, Muggle money easily forged, etc.)
Kill the Spare
There's something in Half Blood Prince (don't have the book to hand) about a fund for poorer students. Dumbledore tells Tom Riddle this. Whether this is just to help out with books and robes I don't know.
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I'm guessing that students wouldn't pay tuition since then there would be no "public magic school". I expect that the majority of the school's operating costs are covered by the Ministry of Magic.
Also, the school has a board of governors and if I am correctly interpreting wikipedia's explanation for "board of governors" that would indicate that Hogwarts is a public school.
It would be in the Ministry's best interests to ensure that all children of magical ability are given the opportunity for a magical education, otherwise they'll never really learn to control their magic and will likely end up endangering the International Statute of Secrecy.
Just my two Knuts worth, hope it helped.