Chinchillas bathe in chinchilla dust.  It is required to keep their fur in good condition. 
We currenty have Hess Pumice for our dust.
Do you just need to order dust?  Get 11 pounds in a medium flat rate box (USPS priority shipping) for $41.00.
Price includes:
$24.75 - 11 pounds Blue Sparkle Dust
$16.25 - USPS Flat Rate Shipping - Medium Box & Handling
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  Please note that if you order this flat rate box of dust, nothing else will fit in the same box.  Additional items ordered will either ship separately or be included with the dust in a large flat rate box if possible.