See if the following applies to your situation
See
https://www.irs.gov/uac/about-publication-538
I believe that even if you might not need to keep "inventories";
you would have to account for the "inventory" as supplies and deduct the
cost of the supplies either when sold (or disposed of), or when paid for....whichever is
later. Thus, I don't think that you can pay for the supplies in 2015
and deduct the cost if the supplies weren't sold until 2016, etc.
But read the publication and the references in the publication carefully.
See also Pub 535 for general business expenses
https://www.irs.gov/uac/about-publication-535
**Disclaimer: Effort has been made to offer correct information; but due to the discussion forum limitations, the poster disclaims any legal responsibility for the accuracy of the poster's response**
