Police your Planet by Lester Del Rey — Read

All that day, the three rocket ships sat out on the field. Nobody went up to them, and nobody came from them; surprisingly, Wayne had found the courage to ignore them. But rumors were circulating wildly. Bruce Gordon felt his nerves creeping out of his skin and beginning to stand on end to test each breeze for danger.

With the credit they'd accumulated in the fund, nearly all their collection was theirs. Gordon went out to do some shopping. He stopped when his money was down to a hundred credits, hardly realizing what he was doing. When he went out, the street was going crazy.