This OpenSource project allows you to use various models, including those from OpenAI itself and some free ones like Google Gemini, Cohere, SambaNova, Groq, and Cerebras.
It's worth noting that Google Gemini is among the best in the LLM Arena.
Why is it free? Google provides a free API with up to 1500 requests per day if it's a Flash model, and 50 requests for the Pro model.
Google isn't the only one; there are several other free options.
Interface: https://eliaspereirah.github.io/OrionChat/