What's a good way to give a limited amount of money to the LLM, say like 2k or 5k or something. But keep it completely separate from my identity.

Like I want the LLM to have a bank account and he can do ANYTHING with that bank account that he wants. But he can't fuck anything up that has to so with me. He only has 2 - 5k

Form an LLC, open bank account for the LLC, and use that.

Idk how you could at least in the US. Closest thing off the top of my head would be one of those checking accounts you can setup for kids. It would still be tied to you.

If you want Anthropic (or others) but anonymously, what you do is use https://openrouter.ai/pricing and fund your account from any of your preferred cryptos.

Solana/Ethereum