5 U.S.C. § 5901 Uniform allowances
(a) There is authorized to be appropriated annually to each agency of the Government of the United States, including a Government owned corporation, and of the government of the District of Columbia, on a showing of necessity or desirability, such sums as may be necessary to carry out this subchapter. The head of the agency concerned, out of funds made available by the appropriation, shall—(1) furnish to each of these employees a uniform at a cost not to exceed $400 a year (or such higher maximum amount as the Office of Personnel Management may establish under section 5902); or (2) pay to each of these employees an allowance for a uniform not to exceed $400 a year (or such higher maximum amount as the Office of Personnel Management may establish under section 5902). The allowance may be paid only at the times and in the amounts authorized by the regulations prescribed under section 5903 of this title. When the agency pays direct to the uniform vendor, the head of the agency may deduct a service charge of not more than 4 percent.
(b) When the furnishing of a uniform or the payment of a uniform allowance is authorized under another statute or regulation existing on September 1, 1954, the head of the agency concerned may continue the furnishing of the uniform or the payment of the uniform allowance under that statute or regulation, but in that event a uniform may not be furnished or allowance paid under this section.
(c) An allowance paid under this section is not wages within the meaning of section 409 of title 42 or chapters 21 and 24 of title 26.