One further point of fact: the Portland Police has made a well-publicized claim that the protests have cost the City of Portland over 6.2 million dollars. That figure represents the total amount of police overtime pay which has been incurred since the protests began, but it conveniently ignores the fact that the Portland Police Bureau was already racking up tons of overtime before the protests.
A recent official audit of PPB found that although PPB claims that its constant, massive overtime expenditures are made necessary by chronic understaffing, PPB documents said overtime so poorly that it is impossible to determine the actual justification for any police overtime. Note that due to the terms of their union contract, the Portland police (and only the police) are exempt from City anti-corruption regulations prohibiting the use of City jobs and equipment for personal gain; thanks to this exemption, police officers are able to moonlight as private security while being paid by the City at all-overtime rates.
In short: the protests are certainly causing police expenses to spike, but not by the claimed 6.2 million dollars.