SDCL § 10-46-31: Amounts of tax paid on conditional sales or installment contract receipts.

If tangible personal property or any product transferred electronically is sold under a conditional sales contract, or under any other form of sale wherein the payment of the principal sum, or a part thereof, is extended over a period longer than sixty days from the date of the sale thereof, the retailer may collect and remit for each month that portion of the tax equal to the rate of tax as provided for in this chapter of that portion of the purchase price actually received during the month.