Whoever sells or offers for sale for use on any public highway in this State any traffic-control device which does not conform to the Delaware Manual on Uniform Traffic-Control Devices for Division of Highways shall be fined not less than $25 nor more than $1,000 and shall make restitution to the purchaser in an amount equal to the entire sum originally paid for the device or devices. In the event a sale consists of the sale of more than 1 separate device, each sale of each separate device shall constitute a violation of this section.