The list price should consider all the manufacturing expenses (production, transportation, fees and taxes, and so on) plus the earnings you want in order to reach the desired profit margin. If you are a consumer and want to calculate the list price of a discounted product, use the following formula:
SP = LP - LP*(D/100)
Where SP equals the sale price of the item, LP equals the original price of the item, and D equals the discount percent of the item.