You can get decent results with much less these days, actually. I don't have personal experience (I do have a 24GB GPU) but the open source community has put a lot of work into getting models to run on lower-spec machines. Aim for smaller models (8B parameters is common) and low quantization (the values of the parameters get squished into smaller numbers of bits). It's slower and the results can be of noticeably lower quality but I've seen people talk about usable LLMs running CPU-only.