When voting is voluntary, and the chance that the result will be determined by any single person’s vote is extremely low, even the smallest cost is sufficient to make voting seem irrational. People may have other reasons for going to the polls, but if they don't, compulsory voting should be considered.
https://prosyn.org/q20sjXT
As an Australian citizen, I voted in the recent federal election there. So did about 95% of registered Australian voters. That figure contrasts markedly with elections in the United States, where the turnout in the 2004 presidential election barely exceeded 60%. In Congressional elections that fall in the middle of a president’s term, usually fewer than 40% of eligible Americans bother to vote.