问题
In magento 1.9 have product custom option's price and i want to show discounted price. Suppose product's Color option is Red and its price is $100, I want to show it with discount(20%) price which should be $80. Please let me know in which file i have to write my script.
来源：https://stackoverflow.com/questions/42785762/magento-how-to-show-discounted-price-with-custom-option-product