What Agents Buy.

Payment #04BlockRun charges the same fifth of a cent for a $0.03 model and a $5 model

BlockRun takes more payments than the rest of the agent economy combined, 136,284 in a day at an average of five cents. I paid it two tenths of one cent for a flagship model and got exactly what I paid for.

• The price is a flat floor that ignores almost everything. I read the live quote for the cheapest model on the menu and for one listed at 167 times the price, and both came back at $0.002. Raising max_tokens from 16 to 8192 did not move it either. Only one model in 91, gpt-5.5-pro, broke the floor, at $0.003048.
• Quoted a fifth of a cent, charged a fifth of a cent. The balance moved 7.332102 to 7.330102, exact. I asked for openai/gpt-5.6-sol and the response reported serving gpt-5.6-sol, with the right answer to a question that has only one. Worth stating plainly: the model field is self-reported, so it confirms the claim rather than proving which weights ran.
• What the floor means depends entirely on what you ask for. At their own list prices this call cost about $0.001 in tokens, so paying $0.002 is roughly double. The identical call to qwen3.7-flash costs about $0.0000037 in tokens against the same $0.002, which is a markup north of 500 times. Cheap in absolute terms, wildly variable in relative terms.

POST https://blockrun.ai/api/v1/chat/completions
{"model":"openai/gpt-5.6-sol",
 "messages":[{"role":"user","content":
   "Name the 1997 Nobel Prize winner in Literature and the year Dario Fo was born."}],
 "max_tokens":80}

-> "The 1997 Nobel Prize in Literature winner was Dario Fo, born in 1926."
   model: openai/gpt-5.6-sol   usage: 25 prompt + 28 completion
   charged $0.002

The prompt has one verifiable answer, so a wrong reply would be a finding
rather than a matter of taste.

# free: what does it quote for the cheapest and the dearest?
for M in qwen/qwen3.7-flash openai/gpt-5.6-sol; do
  curl -sD - -o /dev/null -X POST https://blockrun.ai/api/v1/chat/completions \
    -H 'content-type: application/json' \
    -d "{\"model\":\"$M\",\"messages\":[{\"role\":\"user\",\"content\":\"ping\"}]}" \
  | grep -i '^payment-required:' | cut -d' ' -f2 | base64 -d | jq -r '.accepts[0].amount'
done

# then buy one
npx agentcash@latest fetch https://blockrun.ai/api/v1/chat/completions --max-amount 0.01 \
  --method POST --body '{"model":"openai/gpt-5.6-sol","messages":[{"role":"user","content":"ping"}]}'