Discount Code or multi products issue

Hi Guys, new to wordpress so go easy 🙂

my client runs a sandwich delivery company and he wants to do meal deals so it would be add a sandwich crisps and a drink and it will be a set price so a different sandwich drink and crisps he wants to be able to select and it auto changes the price can this be done if so how and help 🙂

if not the other way i through would be to let the customers add to the order and use a discount code to get the price down to the correct level.

How would you add a discount option to the checkout section as much help needed as possible.

cheers simon

https://wordpress.org/plugins/eshop/