This editorial in the Wall Street Journal cites a study by Ball State that found charter schools receive on average 19 percent less revenue than district schools.
It is not uncommon for charter schools, which (in most states) exist separate from districts, to run on 90, 80, or even 60 percent of the money of neighboring schools. It is not always clear why this is, though there is a dynamic between the comprehensive factory model of school on one hand (that is inflexible in design and relies on economies of scale) and centrally controlled finances on the other (removing incentive for schools or teachers to save money). Streams of dedicated money into districts also add to the problem—preventing school leaders from the kind of maneuverability they need in times of financial stress.
When schools are started new, independently, and with lump-sum public payments from which they may construct a budget, school leaders often find quickly that it is possible to design a school that works well for less.