(a) The sales and use tax does not apply to a personal, professional, or insurance service that:

(1) is not a taxable service; and

(2) involves a sale as an inconsequential element for which no separate charge is made.

(b) The sales and use tax does not apply to the sale of an optional computer software maintenance contract if the buyer does not have a right, as part of the contract, to receive at no additional cost software products that are separately priced and marketed by the vendor.

(c) The sales and use tax does not apply to the use of a taxable service obtained by using a prepaid telephone calling arrangement.