There is hereby imposed an excise tax of four and two-tenths percent on the gross receipts from the sale, resale, or lease of farm machinery, attachment units, and irrigation equipment used exclusively for agricultural purposes. However, if any trade-in or exchange of used farm machinery, attachment units, and irrigation equipment is involved in the transaction, the excise tax is only due and may only be collected on the cash difference.
SDCL 10-46E-1