Boomwhackers are a marvelous instrument if you buy  enough for a whole class. They are pitched and colour coded. They are great to sing with. They are relatively quiet but still satisfying and energetic.
We sell  6 pentatonic sets for £105 + VAT
That is 36 instruments for less than £3 each

We have over 600 so can run a whole school session if you wish.
Have a look at the videos.