By definition, an amateur boxer makes no money from the sport. Professional boxers (who earn money for their fights) are not allowed to compete in the Olympics.
Amateur and Olympic boxing is governed by the International Boxing Association (AIBA), a Swiss organization. Professional boxers - or those who earn money for their bouts - are not permitted to compete in the Olympics.
In 2010, the AIBA initiated a semi-professional league called the WSB or World Series of Boxing which would pay competitors but still allow them to qualify for Olympic competition. Salaries in the league range from $25,000 to $300,000 per year.