That would depend on the grade level. In grades three or four, I would start with recorders. They are great for getting students started using their air correctly, introducing fingerings and increasing reading skills. By grade six, guitar class is a great way to keep students engaged, and guitars are very reasonably priced. Of course, choral music is extremely cost-effective at any age! I hope this answers your question. If you need any more information, please feel free to contact me for follow up! Thanks!