Prestashop Discount Code

[login to view URL] Hi We require coupon to facilitate following: Chicken Mains $ 10.90 Lamb Main : $ 9.90 And same with other categories when customer add his voucher code. Customer can choose any combination of mains eg 2 chicken mains, 1 lamb mains, 2 goat etc. Upon entering coupon code price must be adjusted in shopping cart and at the backend ability to create coupon codes with discounted price. If that coupon code is outdated error message must clearly state "Coupon code you entered has passed its validity date" Due to our security policy we will be unable to provide any password for domain. Hence module must be self installed.