You can use something like OpenRouter, which lets you access essentially all commercially available models. Including open-source models. There are no rate limits.
You pay a different rate per model (OpenRouter shows the pricing transparently). You load your account with credits. I use it daily (undoubtedly far more than the average user) and loaded 50$ with credits five months ago, but I still have over 1/2 of it left.
I think it is hard to believe that Kagi would be any cheaper and have no rate limits.
Keep in mind that, while OpenRouter gives you the upstream price for OpenAI/Anthropic models (so you pay the same per token), there's a loading charge, so if you want to load $10 in credits you pay $12 or so.
This means that it's more expensive than calling OpenAI directly, even though they have the same price per token.
Where the loading charge is amortized over all the calls made.
If you want to use precisely one API, paying directly for that API is cheaper. However, that's only true with closed-source providers. Anyone can host a server running llama 3.1 that OpenRouter could (in theory) use, bringing price competition to model cost. Closed-source models have a monopoly and can set their price wherever they want.
I'm okay with spending an extra 2$ every six months to access the APIs of any model I want.
LibreChat is also one of the few LLM chat interfaces that works with both external APIs (OpenAI, Anthropic, etc) and local ones (hosted via Ollama, etc) out of the box.
If it has a downside, I'd say its a little more involved to get setup, lots of docker containers, etc then a more batteries-included approach like Jan.
There's also BigAgi (really a weird ass name - probably hurting them) that is good for the same use case. Just paste in your API key and you get a really nice UI to chat through at-cost.
You pay a different rate per model (OpenRouter shows the pricing transparently). You load your account with credits. I use it daily (undoubtedly far more than the average user) and loaded 50$ with credits five months ago, but I still have over 1/2 of it left.
I think it is hard to believe that Kagi would be any cheaper and have no rate limits.