"explain how freedoms for former slaves were economically limited from 1865 to 1900? "

Poll taxes developed in the late 19th century as a branch of the Jim Crow laws. Poll taxes were meant to discourage former slaves from voting by, hence the name, taxing their votes before they can cast them. Around that time money was tight and former slaves could barely afford to pay for the shoes on their feet. Thus doing so, (passing the Poll taxes) the former slaves were at the mercy of the government because it was a win-win either way for them. They devised a plan that could ruin former slaves economically.