It’s a common misconception that property taxes are lower in unincorporated areas than they are in an incorporated city or town.
Sales taxes are lower in unincorporated areas, since most cities have their own sales tax. If you register a new car in one of those cities with a sales tax, you’ll pay thousands that you wouldn’t pay registering it in an unincorporated area.
Property taxes are another matter. Take the City of Golden, for example. The mill levy for the city is 12.34 mills. Here’s the full mill levy for such a home:

If you have a Golden address but are not within the city itself, you have separate mill levies for county law enforcement, fire protection and quite possibly for water and park districts that can total far more than Golden’s mill levy, which includes all those services. If you’re in a newer subdivision, you could have an additional big mill levy for a “metropolitan tax district” which was created by the developer to pay for infrastructure. Here’s the mill levy for a home in Table Rock, that subdivision on the north slope of North Table Mountain, which does have a metro tax district:
