We just started a service different open source models and with an OpenAI compatible API [1]. The pricing isn't final and we haven't officially launched yet but you should be able to save at least 75% compared to GPT 3.5.
Hey BrunoJo, saw your posts on a couple of threads. Love what you're doing at lemonfox! Do you have any troubles with finding cheap GPUs to host models on? If so, I'm working on service that provides a single API and UI for launching cloud GPUs across 10 different cloud providers so you can always find available gpus. Let me know if this might be useful for you!
[1] https://lemonfox.ai/