Today’s approximate costs (tiny tx: consume nonce OR emit 3…

Today’s approximate costs (tiny tx: consume nonce OR emit 32-byte audit hash OR update a session key)
- Ethereum L1: ~$0.50–$5.00 per tx (not for per-prompt; fine for periodic anchoring).
- Base / Optimism: ~$0.002–$0.05 per tx.
- Arbitrum One: ~$0.01–$0.05 per tx.
- Polygon PoS: ~$0.0005–$0.005 per tx.
- zk rollups (zkSync/Scroll/Linea): ~$.005–$.05 per tx.
(These swing with gas and token prices.)