The school, located about halfway between Balclutha and Owaka in the Catlins, has three classrooms and about 60 pupils.
Pupils run a flock of sheep on a 2ha paddock at the school and trade them as part of a programme to learn about farming. All of the 20 lambs the pupils offered sold for between $165 and $173 each.
Pupil Lachlan McKenzie, of Paretai, said the money would be used to buy ewes with lambs at foot.