> The protocol boast "no fee" but that's deceptive: if it's based upon a blockchain, there will be transaction fees.

These days many transaction types onchain are completely free and subsidized because gas costs are subcent[1].

x402 functions predominantly on L2 networks like Base, where individual tx costs between agents are generally not a factor.

[1] https://www.gasfees.io/

According to that site Base USDC fee is 1/8th of a cent. The x402 whitepaper says 1/100th of a cent so I'm not sure what accounts for the discrepancy; maybe Coinbase is willing to subsidize fees in some cases.