I am often disturbed by the 90 gold fee healers charge, mainly due to it being beforehand, and the refusal of treatment without it, no matter the amount or percentage of HP I have. Essentially a mixture of "Don't you care" and "Do your job". Though this might have lore implications that I think people are avoiding. The services they are offering are not life saving, but prevention, something which is not traditionally covered without a form of prepayment or insurance. After all, Milletians are unable to die by conventional means, whereas the regular inhabitants have been shown to be susceptible to death.
One may ask, how can they tell? A lot of it can be determined from the condition of the patient, from their gait to their wounds. Many Milletians have been shown to be completely "fine" at any HP level, with no movement speed reduction pointing to the existence of debilitating wounds, among other things. Milletians are capable of healing their own HP, whereas normal people can be suggested to have a typical, human enough frame, whose injuries are real enough to cause death, while Milletians merely faint before resurrecting, alongside other abilities including rebirthing.
Therefore, the treatment is not necessary for Milletians in any sense, thus any injury that would hurt a regular inhabitant would be considerably trivial to them and their abilities. After all, if resting can restore you to tip top shape, it is usually not that bad.
Thus, Manus and the other healers have no legal obligation to provide what is essentially preventive treatment without charging first, because it is not life saving in anyway, and can be healed by the Milletians. Should they?
Don't be greedy. Be glad it is only 90 gold.