In my opinion, a fair price should be charged rather than what you need to survive.
Despite the fact that you look after the business, you are still an employee of the business, and while you have a right to be paid, the business needs its own portions as well.
Underbidding is not the best idea if you have all the necessary certifications, insurance, bonds, licenses, office rental, and other expenses. We can help if you send private message.