Help running ai on my computer locally.

I've been getting more into AI lately but I keep running into rate limits and I can't afford to get a higher subscription. I've heard people talking about possibly saving money by running these AI models on my computer locally but I need help understanding what my computer is capable of and what it takes to set this up and also how to do it in the right way, cause I've heard stories of people getting screwed over by setting up their AI wrong.