The people of Umuofia give their mandate to Marcus and get him elected as their representative believing that he would work for their welfare and upliftment. However, as his term rolls by, they witness a substantial change in Marcus’ status and wealth, while the people’s status remains the same. People realize how politics can make someone rich and powerful. They regret that they had underrated the power of their mandate, and so decide to demand a share of his earnings to cast their vote.
That is why, in the whispering campaign, when Roof offers each one of the two shillings, they tell him that it was too shameful to accept just two shillings from Marcus for their vote because Marcus was no longer a poor man and was doing great things like a great man. Then they agree to cast their vote taking four shillings each.
An election process in any democratic set up has high intrinsic value because it symbolizes people’s mandate and the elected representative becomes the voice of those people. Naturally, when the voters of Umuofia demand money to vote for Marcus, it only means that their real mandate has not given them what they needed and they remain in abject poverty as before. They have lost faith in elections as a means to achieve their welfare. The previous election may have failed them but they ought not to become corrupted. That will pave the way for further deterioration by building obstacles in the path to their own development. They are not right in demanding money.