This stuff is changing rapidly. The market seems to be very frothy and who knows what will happen in 6 months with nVidia and all the rest.

If I were starting out, I would play around with what's available online and figure out what needs to be done locally and then start picking out parts.

https://www.reddit.com/r/LocalLLaMA/comments/1ajijk8/hardware_guide/

https://www.theregister.com/2024/03/17/ai_pc_local_llm/

Etc.

Cheers,
Scott.