I just found that listing on EBay. Yes, Harry Potter books go for a great deal of money.
You need money to buy books. Fortunately, the first hand book industry is a stalling, fading, Kindle reading pile of shit. The second hand book industry on the other hand, is a prospering, growing and ever changing thing. The low-hanging fruit of the second hand book market is so good, that Goodwill has opened a chain of book stores all over the United States. One just opened next to my house in a great area of the city.
The average book at Goodwill (I'm just using Goodwill as an example, and it's pretty common) is about $1.00. On certain days they are half off, or have a colored tag on it which means it's on sale. Hard backs are normally $1.99, and again, you can get them half price if you time it right. Go often, buy many.
"But Major! I'm broke!"
If you can't afford a $10 investment at least once a week, then book collecting of any kind is not for you. In the event you just need some starter money, try my little experiment as follows.
1) Go to the Paperback exchange/Goodwill/Garage Sale. Visit as many as you have to. In my neck of the woods if takes a good weekend to get some great books together so it does take some time.
2) Buy 4 or 5 Fantasy or Science Fiction hard covers. Don't spend more than $1.00 or $2.00 on each one. This is important.
3) List the books on eBay for the going rates. You may only get $3-5 per book. This is normal. Shipping for each book is around $2.00.. in that ball park. Charge around $.50 extra. This can be you're gas money for all the driving you just did to the local thrift stores.
4) 5 books, at an average of $2.00 per book, is a $10 profit. Now you have money to buy more books next weekend.
For those who are still paying attention, you made double you're money back. It's only $10 extra, but on some occasions you can find books like i found this morning with my wife: A Harry Potter First edition.. this one happen to be The Prisoner of Azkeban.
It's a quick story, but about 13 miles from my house in Florida is a Super Goodwill. It's a giant warehouse sized thrift store that keeps on giving. I go here at least twice a week and find something to keep for myself or sell. I'm at the point now in my collecting career that I keep most of what I buy and just sell the duplicates, so this place is great for me. All in all, Super Goodwill is amazing for books. I brought my wife with me so she could look at Christmas stuff while I checked out the books, toys and movies. She followed me over to the books and we looked together at some stuff. Someone had offloaded their Starwars: New Jedi Order book series and there were about 25 of those going for .50 cents each. Those alone are great for someone looking to expand on their Starwars collection or to complete a set. I found a few Terry Goodkind paperbacks I did not have, or thought I did not have, a Dragonlance novel not written by Margeret Weis, and a Forgotten realms novel, which I will always pick up and I'll explain why later.
Looking in the hardbacks for about ten minutes I spotted The Prisoner of Azkeban sitting on a low shelf, my wife saw me pick it up, and came over. "First edition?" She asked. It's about all she knows about book collecting. Firsts.. they are worth coin. I turned it to the title page and confirmed that it was, closed it, and tossed it into the cart with the others. This particular book is the fourth first edition Harry Potter book I have found in a month at the same Goodwill. I paid $1.99, and with a quick look up on EBay from my smart phone, I learned it is worth about $50 on any given day, sometimes more. I knew this, but I always confirm. The going rate does change, and J.K. Rowling just released a new book, which generates some interest. I have a set of First edition Harry Potter books in PB and HC that i would not sell, that i bought new years ago. Anything that I buy after that goes to eBay to fund more ventures like this. That $50 just paid for the gas money to get there, my wife's Christmas crap, and lunch for all three of us, with some left over for another trip later in the week.
Harry Potter hard backs were printed in mass. First editions are not rare, I repeat.. NOT RARE. People wait in lines around a building all day, millions are sold in the first few hours. So why do people pay a premium? Really I don't know, and I don't ask questions. Buy them as you see them, keep some for yourself and sell the rest. You will encounter more of these books than any other and you will learn to love them to keep you in the book collecting biz. If I lost my job tomorrow I could book hunt and sell off duplicates to make ends meet. You can do the same.
As a side note, when you sell a book, prices are all over the place. First edition books going from seriously over $1,000 to $10. How do you price the book you just bought so it will sell? Offer cheaper shipping. Take great pictures. Look in the lower end where most of the prices are grouped up and try to be right in the middle. If it does not sell right away, give it some time, build up an inventory. The sales will come in.