Link to Tennessee Dept of Revenue where the application for Amateur Radio License Plates is located. Currently on page 2.
https://www.tn.gov/revenue/title-and-registration/forms.html
The Tennessee Legislature eliminated the requirement for paying a $25 fee for amateur radio plates. The governor signed the new law on May 21, 2018 and it became effective May 23, 2018. You are no longer required to pay a $25 fee if you do not belong to ARES or have approval from your county EMA director.
Text of the bill as enacted is as follows:
SB1588 SENATE BILL 1588 By Bell AN ACT to amend Tennessee Code Annotated, Title 6, Chapter 54, Part 1 and Title 55, Chapter 4, Part 2, relative to amateur radio license plates. BE IT ENACTED BY THE GENERAL ASSEMBLY OF THE STATE OF TENNESSEE: SECTION 1. Tennessee Code Annotated, Section 55-4-229(e)(2), is amended by deleting the subdivision and substituting instead the following: (2) Notwithstanding this part to the contrary, to be eligible for an amateur radio license plate without paying the fee prescribed by § 55-4-203(a)(4)(A)(ii) in addition to the regular fee for the plate, the registrant shall furnish proof to the commissioner, through the county clerk, that the registrant: (A) Has credentials approved by the county emergency management director; or (B) Holds a class license as an amateur radio operator issued by the federal communications commission. SECTION 2. This act shall take effect upon becoming a law, the public welfare requiring it.