How much money do you need to buy a planet?

Excuse me, but could you clarify something for me? The notion of buying a planet seems rather far-fetched, given that they are celestial bodies beyond our direct ownership or purchase. Could you elaborate on what you mean by "buying a planet" and how much money, hypothetically speaking, might be involved in such an endeavor? Are you referring to space exploration ventures, terraforming projects, or perhaps some other aspect of extraterrestrial economics that I'm not aware of? I'm genuinely curious to understand the context behind your question.