The Third Estate was made up by the merchants, peasants, and the laborers (bourgiosie). The bourgiosie were the only ones that were able to address the Third Estate grievances.
One of the main grievances of the Third Estate were the high taxes. The First Estate (clergy) took control of the Third Estate and made them do the harder work since they both voted that they should be the ones that had to be paying the taxes making it two against one and the vote of the Third Estate didn’t mean much. This action would make it impossible for the Third Estate to be able to make any gains in their life economically and politically. It became very difficult for the peasants to be able to pay for taxes. As a result, the peasants had times when they became short on the food and sometimes were not able to eat.
On top of everything else, the price of bread increased too much for them to even be able to afford to buy it. They had families to provide for and with starvation comes many health problems. However, all their grievances they had could be administrated to the monarch. The peasants had no voice, therefore they were unable to put forth an argument. The only solution they had was to revolt, also known as the Great Fear. Even then, they did not get much change. These were crucial reasons for them to support the French Revolution.