Seeking Advice on Building a QA Chatbot for Knowledgebase Documentation

I’m relatively new to the world of AI and I’m currently tasked with building a QA chatbot for our knowledgebase documentation. However, I’m facing a bit of a budget constraint, and using Large Language Models (LLMs) seems to be quite expensive for our project. I’m seeking advice on alternative CPU models and the right approach to building this chatbot effectively within our budget constraints.