(a) In this section, “standard presumptive value” means the private-party transaction value of a motor vehicle, as determined by the Texas Department of Motor Vehicles based on an appropriate regional guidebook of a nationally recognized motor vehicle value guide service, or based on another motor vehicle guide publication that the department determines is appropriate if a private-party transaction value for the motor vehicle is not available from a regional guidebook described by this subsection.
(b) If the amount paid for a motor vehicle subject to the tax imposed by this chapter is equal to or greater than 80 percent of the standard presumptive value of the vehicle, a county tax assessor-collector shall compute the tax on the amount paid.

(c) If the amount paid for a motor vehicle subject to the tax imposed by this chapter is less than 80 percent of the standard presumptive value of the vehicle, a county tax assessor-collector shall compute the tax on the amount that is equal to 80 percent of the standard presumptive value of the vehicle, unless the purchaser establishes the valuation of the vehicle as provided by Subsection (d).
(d) A county tax assessor-collector shall compute the tax imposed by this chapter on the valuation of a motor vehicle if the valuation is shown on:
(1) documentation, including a receipt or invoice, provided by the seller to the purchaser of the vehicle, but only if the seller is a motor vehicle dealer operating under Subchapter B, Chapter 503, Transportation Code, or under similar regulatory requirements of another state; or
(2) an appraisal certified by an adjuster licensed under Chapter 4101, Insurance Code, by a motor vehicle dealer operating under Subchapter B, Chapter 503, Transportation Code, or by an adjuster or motor vehicle dealer licensed or operating under similar regulatory requirements of another state.
(d-1) An appraisal described by Subsection (d)(2):
(1) must be on a form prescribed by the comptroller for that purpose; and
(2) must be obtained by the purchaser of the vehicle not later than the 20th working day after the date the motor vehicle is delivered to the purchaser or is brought into this state, as applicable.
(e) On request, a motor vehicle dealer operating under Subchapter B, Chapter 503, Transportation Code, or under similar regulatory requirements of another state shall provide a certified appraisal of the valuation of a motor vehicle. The comptroller by rule shall establish a fee that a dealer may charge for providing the certified appraisal. The county tax assessor-collector shall retain a copy of a certified appraisal received under this section for a period prescribed by the comptroller.
(f) The Texas Department of Motor Vehicles shall maintain information on the standard presumptive values of motor vehicles as part of the department’s registration and title system. The department shall update the information at least quarterly each calendar year and publish, electronically or otherwise, the updated information.
(g) This section does not apply to a transaction described by § 152.024 or 152.025.
(h) This section does not apply to a motor vehicle disposed of in accordance with Chapter 2303, Occupations Code, or Chapter 70, Property Code, or sold by a federal, state, or local governmental entity at public auction, including an auction authorized by Chapter 683, Transportation Code.
(i) This section does not apply to a motor vehicle that is eligible for a specialty license plate under § 504.501, Transportation Code.
(j) The requirements of § 501.145, Transportation Code, continue to apply to a transferee of a used motor vehicle who obtains an appraisal under Subsection (d)(2), and obtaining an appraisal does not modify those requirements.