James Bulger works at a sandwich shop in Ames, Iowa. During his coffee break each afternoon, he enjoys a candy bar that his employer sells to him at an employee discount. Candy bars are not exempt (as food) from sales taxes in Iowa, and his employer charges him sales tax on the purchase. Recently, James noticed that his employer was charging him sales tax on the retail sales price ($1), not the employee discount price ($0.80) that James actually pays. What is the proper amount to calculate the sales tax on, the actual (reduced) price or retail price?