Mistral Vibe is cheap for what you get - I haven't run into limits yet, and you can use the same API key for the CLI for their API to run Codestral, Mistral large, etc. Le Chat is great as well, especially research mode. Afaik their models are running on Cerebras so you are never waiting for a response.

Obviously Opus and Codex are better for coding, but I dont really use it much to generate actual code so I don't think I'm missing much.