Well, he might choose a house in a wizarding village. Maybe it's a small cottage with a charmed garden full of magical plants. He could use his Triwizard Tournament winnings to pay for it.
The house elf might be very grateful. Harry is known for his kindness, so the elf could see this as a chance for a better life. It might immediately start serving Harry with great enthusiasm, believing that Harry will be a fair and good master.
In this fanfiction, Harry Potter might be facing a new situation in the Muggle world. Buying a car could be a sign of his further integration into Muggle society. Maybe he uses his wizard money to buy a really cool and unique car, like a classic convertible.
Well, he might use the house elf to keep his new house in order. The elf could help with cleaning, cooking, and protecting the place from unwanted intruders. It would be interesting to see how Harry, who has always been against the unfair treatment of house - elves, would manage this new relationship with an elf he owns.
Ron might be there too. He could use his skills in handling magical creatures to populate the island with friendly ones. And he could also help with fishing in the surrounding waters using magic, providing food for those on the island.
Yes, there might be. The Harry Potter fandom is vast, and fanfiction writers come up with all sorts of creative and unique ideas. You can try searching on popular fanfiction websites like Archive of Our Own or Fanfiction.net. There could be a story where Harry Potter is involved in buying a marriage contract in some alternate universe or as part of a very different plotline created by the fanfiction author.
One challenge would be the goblins. They are very protective of Gringotts and would not easily give up control. They have their own laws and traditions regarding ownership. Harry would have to deal with their resistance and find a way to convince them or negotiate with them.
Well, perhaps Harry, tired of the wizarding world's chaos, decides to buy an island for some peace. He could use magic to build a unique, hidden mansion there. Maybe he'd invite his closest friends like Hermione and Ron to visit, and they'd have magical adventures on the island that are different from those in Hogwarts.
Maybe Harry Potter, after all his adventures, decides he needs a peaceful place. He uses his wizarding money to buy an island. He might turn it into a magical sanctuary for magical creatures, away from the prying eyes of Muggles.
He might want a place of his own, away from the chaos of Hogwarts and the wizarding world's constant threats. A building could be his private sanctuary where he can relax and practice magic without being bothered.