I'm banned from using the free options. At some point they flagged my account as having engaged in model training against their ToS. This despite my account using around £15 worth of tokens over several months, nearly entirely through BYOK providers.
The handful of times I did try a free model is when I used their chat interface to quickly compare a few open weight models with a single prompt. That's the only usage I can think which could have triggered the block on my account. Even still, what's the point in have the simultaneous chat feature if using it veers so quickly into a ToS violation.
Their support is beyond useless in helping understand the situation. I don't think I managed to speak to anyone other than Tony Bot (or whatever it was named).
Edit:
Total usage over 1 year:
Claude Sonnet 4.6 $8.80
Gemini 3.1 Pro Preview $6.71
Claude Opus 4 $6.19
Claude Opus 4.1 $7.49
Gemini 2.5 Pro $10.06
Claude Sonnet 4.5 $12.74
GPT-5 Codex $2.56
Grok 4 $4.39
Gemini 2.5 Flash Image Preview (Nano Banana) $1.88
GPT-5 $7.30
Others $7.99
Since you're BYOK, have you tried self-hosting LiteLLM? It's what I use for the BYOK option on my service.