Hillary Clinton was paid $675,000 for just three speeches by banking giant Goldman Sachs.
Ms Clinton generally commands a minimum of $225,000 per speech, or over four times as much as the $52,000 (£36,000) the average American citizen earns in a year. She once pocketed $315,000 for a 20-minute address to Ebay staff.
Mr Sanders' income, by way of contrast, is largely derived from his $175,000 Senate salary. His wife, Jane Sanders, makes $5,000 annually as a radioactive waste disposal commisioner, and the couple also receive social security benefits and a small annual pension.