Authorizing a merchant to round the portion of the price of a certain transactions for which a customer pays using cash in a certain manner or round the amount of change due to a customer in a certain manner; providing that certain provisions of the Act shall preempt existing regulations, rules, and ordinances that conflict with certain provisions of the Act; and altering the definition of "taxable price" for certain purposes to clarify the exclusion from tax of a certain amount collected due to rounding the price.