In 1971 the US Supreme Court ruled on this very issue, stating that if it costs more than what the average person can pay for, then paying for speaking restrict

In 1971 the US Supreme Court ruled on this very issue, stating that if it costs more than what the average person can pay for, then paying for speaking restricts freedom of speech. They compared the cost to mail a letter vs a commercial. At the time they stated, "$1000 is beyond the reach of the majority." which at the time was what campaign donations were limited to.