A slight correction, he paid zero fee. The 0.5 bitcoin is change, that he got back.
You can see the fee amount further down the page. If he had paid a fee, 0.0001 BTC, or $0.04 worth of BTC, would have been enough to ensure the transaction was included in the next block.
You can see the fee amount further down the page. If he had paid a fee, 0.0001 BTC, or $0.04 worth of BTC, would have been enough to ensure the transaction was included in the next block.