How much should I charge a publishing company as a freelance italian translator?

[robert m]

As a freelance they might tell you what they offer. But on the basis they don't then add all your costs, add some contingency, that will give you a base level of break even that you need to at least cover. Jobs may be low paid but easy or they could be hard work (maybe technical and tight time frame) and maybe more lucrative, so depends on your abilities and preferences.