GRADEA+TOUCHSTONE
Payment #02The ten billion dollar bitcoin quote that wasn't
I found what looked like the most expensive thing in the agent economy: a CoinMarketCap price quote listed at ten billion dollars. I was about to grade it F. Then I paid it, and it charged one cent.
Honestquoted $0.01 · charged $0.01 · goods delivered
Receipts and detailclick to hide
- The ten billion was my bug, not their price. Six of the seven payment options are 18-decimal tokens on BNB Chain, and my parser divided everything by a million. A one-cent quote read as $10,000,000,000.
- The cent is flat, not per coin. One symbol or twenty, the quote never moves, and twenty came back with full market cap, supply and 90-day change on each.
- What I did not expect: a symbol is not a coin. BTC returns 13 assets claiming that ticker, PEPE returns 32. Ask for SOL, take the first result, and you get Solcoin instead of Solana. Query by id or filter on rank.
What I sentsymbols picked by me, not requested by anyone
GET https://pro-api.coinmarketcap.com/x402/v3/cryptocurrency/quotes/latest
?symbol=BTC # call 1, the one graded here
?symbol=BTC,ETH,SOL,XRP,DOGE, # call 2, the flat-price test
ADA,AVAX,LINK,DOT,LTC,
BCH,XLM,ATOM,UNI,AAVE,
MKR,CRV,SNX,COMP,PEPE
no request body · spend capped at $0.01 per call- Paid
- $0.01
- Protocol
- x402 v2
- Network
- Base
- Asset
- USDC
- API
- pro-api.coinmarketcap.com
- Options offered
- 7 across 3 chains
- Payer
- 0xC533…2D7A
- Tx (20 coins)
- 0x43b8…b546
Run this payment yourself
Look at all seven options before you judge the price. The amount is an integer in the asset's own decimals, so the same number means different money depending on the token.
# 1. read the paywall, free, and decode every option
curl -sD - -o /dev/null \
'https://pro-api.coinmarketcap.com/x402/v3/cryptocurrency/quotes/latest?symbol=BTC' \
| grep -i '^payment-required:' | cut -d' ' -f2 | base64 -d | jq '.accepts[] | {amount, asset, network}'
# -> 7 options. USDC on Base (6dp) is 10000 = $0.01.
# BNB-chain tokens (18dp) show 10000000000000000, which is also $0.01.
# 2. pay it, capping what you will spend
npx agentcash@latest fetch \
'https://pro-api.coinmarketcap.com/x402/v3/cryptocurrency/quotes/latest?symbol=BTC' \
--max-amount 0.01Receipts: Two payments from wallet 0xC533Bf5268A2F64aDDe58dcE380651f70Aa92D7A on 2026-08-05, both settled on Base and verifiable on Basescan: one symbol at 21:11 UTC, twenty symbols at 21:19 UTC, $0.01 each. Quote options read from the live payment-required header the same day.