Okla. Stat. tit. 70, § 70-9-108: Additional transportation - Expenses

The board of education of any school district furnishing

transportation is hereby authorized to furnish, in addition to free

transportation to and from school, transportation within or without

the district, within or outside of this state, for children

attending the schools of that district, for the purpose of attending

cocurricular and extracurricular activities. Two or more districts

may enter into agreements for the furnishing of such transportation.

The expense of any such additional transportation shall be paid by

the children so transported, by the school activity or school

organization receiving benefit from such transportation, or from

other private sources. Money so collected shall not be chargeable

to or become a part of the school district's finances.