This title of this project is called "Econmical mobile cases". The purpose of this project were: 1) to study about sufficiency economy and economical mobile cases, 2) make mobile cases by save money 3) to know information about the use of phone for teens. We surveys student ar Kanaratbumrung Pathumthani School about using mobile cases. The conclusion of this project indicated that more than 90% of student at Kanaratbumrung Pathumthani School using mobile cases. Moreover, We hoped that most of student at Kanaratbumrung Pathumthani School will be ready to know about sufficiency economy.