In a county that has adopted the tax authorized by this chapter, there is imposed an excise tax on the use, storage, or other consumption within the county of taxable items purchased, leased, or rented from a retailer during the period that the tax is effective within the county. The rate of the excise tax is the same as the rate of the sales tax portion of the tax and is applied to the sales price of the taxable item. With respect to a taxable service, "use" means the derivation in the county of direct or indirect benefit from the service.
Tex. Tax Code § 323.104