Section 11-301 - Computation of taxThe sales and use tax is computed on:
(1) the taxable price of each separate sale;(2) if a combined sale is made, the combined taxable price of all retail sales on the same occasion by the same vendor to the same buyer; or(3) if retail sales of tangible personal property or a taxable service are made through vending or other self-service machines, 94.5% of the gross receipts from the retail sales.