Almost everyone picks a model by reputation and then never revisits it. The catalogue spans $0.03 to $2.00 per 1M input tokens — a 67× range. If a model at the bottom of that range passes your quality bar, reputation just cost you 98% of your bill.
The only way to know is to test on your own work. Here is the whole method in one command.
One real task — rewriting a support reply — run across the price ladder.
for m in qwen/qwen3.7-flash openai/gpt-oss-120b google/gemini-2.5-flash-lite anthropic/claude-sonnet-5; do echo "--- $m" curl -s https://openrouter.ai/api/v1/chat/completions \ -H "Authorization: Bearer $OPENROUTER_API_KEY" -H "Content-Type: application/json" \ -d "$(jq -n --arg model "$m" --rawfile p prompt.txt '{model:$model, max_tokens:200, messages:[{role:"user",content:$p}]}')" \ | jq -r '.choices[0].message.content' doneFour answers, four price points. Read them before you look at the prices — otherwise you will find quality wherever you expect it.# what each one would cost for 2,000 replies a monthAssuming ~180 input and ~120 output tokens per reply. The frontier model is roughly 74x the cheapest — and every one of those four replies would have been sent.
Your own numbers will differ — token counts depend on your text, and rates move. The arithmetic is what transfers.
Score on acceptance, not on taste
The Sonnet answer is the best writing. That is not the question. The question is: would you have sent it? If the answer is yes for all four, you are looking at a 74× price difference for a preference. If the cheap one would have needed an edit, then it is not cheap — add your own minutes at your own rate and re-do the sum.
| Model | $ / 1M in | Sent as-is | Needed an edit | Unusable | Real cost per accepted reply |
|---|---|---|---|---|---|
| qwen/qwen3.7-flash | $0.03 | 7 | 3 | 0 | $0.00002 + 3 edits |
| openai/gpt-oss-120b | $0.037 | 8 | 2 | 0 | $0.00003 + 2 edits |
| google/gemini-2.5-flash-lite | $0.10 | 9 | 1 | 0 | $0.00007 + 1 edit |
| anthropic/claude-sonnet-5 | $2.00 | 10 | 0 | 0 | $0.00156 + 0 edits |
Knowledge check
A cheap model passes 7 of 10 tasks; a frontier model at 60× the price passes 10 of 10. Editing a failure costs you 4 minutes. When is the cheap model still the right choice?