Collaboration with other schools or academies could improve value for money, e.g. by sharing staff or joint purchasing to benefit from economies of scale.
The DfE have published the outcome of research into collaboratiosns between schools which can be found here:
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/467855/DFE-RR466_-_School_improvement_effective_school_partnerships.pdf
https://www.gov.uk/guidance/schools-financial-efficiency-sharing-best-practice