Most bitcoin transactions include what's called a "miners' fee", an arbitrarily small amount put there as an incentive for miners to include your transaction in

Most bitcoin transactions include what's called a "miners' fee", an arbitrarily small amount put there as an incentive for miners to include your transaction in the blockchain, therefore speeding up the verification of said transaction. These fees will be there even after the last bitcoin has been mined, so there will always be an incentive to mine (provided that bitcoin is still in use by then). https://en.bitcoin.it/wiki/Transaction_fees https://en.bitcoin.it/wiki/Transaction_fees