Live demo. Paying here uses real USDC on Base, sent to Charthouse Ltd (the seller). Price: $0.50.
For $0.50 in USDC on Base you get the right to train AI models on the demo article A short guide to sealed content. First you sign a free message, which moves no money, so the unlock service can tell whether you already hold the licence. Only if you do not can you buy it. Every licence is signed by the unlock service and checked here against its published key.
Waiting for a wallet.
Agents can buy the same licence without a browser; see the guide for AI agents.