Ala. Code § 40-12-84
Any person, firm, or corporation accepting orders or contracts for doing any work on or in any building or structure requiring the use of paint, stone, brick, mortar, wood, cement, structural iron or steel, sheet iron, galvanized iron, metallic piping, tin, lead, electric wiring, or other steel, or any other building material, or accepting contracts to do any paving or curbing on sidewalks or streets, public or private property, using asphalt, brick, stone, cement, wood, or other composition, or accepting orders for or contracts to excavate earth, rock, or other material for foundations or any other purpose, or accepting orders or contracts to construct any sewer of stone, brick, terra cotta, or other material, or accepting contracts to construct highways, bridges, dams, or railroads, shall be deemed a contractor. Every contractor shall procure from the probate judge of the county in which he has his principal office a license to carry on the business of a contractor; provided, that if such contractor has no such office in this state, then he shall procure such license from the probate judge of the county where the contract is to be performed. Every such contractor shall pay a license tax to be ascertained on the basis of the gross amount of all orders or contracts accepted, exclusive of orders or contracts pertaining to state or county road and bridge projects, as follows: If the gross amount of all orders or contracts accepted aggregates $5,000 and not exceeding $10,000, he shall pay the sum of $10; if the amount of such orders or contracts is more than $10,000 and does not exceed $20,000, $15; if the amount of such orders or contracts exceeds $20,000 and does not exceed $50,000, $25; if the amount of such orders or contracts exceeds $50,000 and does not exceed $100,000, $50; if the amount of such orders or contracts exceeds $100,000 and does not exceed $150,000, $150; if the amount of such orders or contracts exceeds $150,000 and does not exceed $200,000, $200; if the amount of such orders or contracts exceeds $200,000, $250; and, when such contractor shall have obtained a license for any year for which he has paid a license tax of less than the maximum above prescribed, he shall not accept any contract or contracts during such year, the aggregate amount of which exceeds the maximum amount for which his license was obtained, unless and until he shall have paid such additional sum as will make the total license tax paid by him for that year sufficient to cover the aggregate amount of such contract or contracts as prescribed above; and unless he pays such additional sum he shall be deemed to be acting without a license. The payment of the license tax in one county in the state, as evidenced by the license or official certificate of the probate judge, shall be sufficient.
Ala. Code § 40-12-84 (1975)