restaurant ecommerce solution

I got a web design lead that owns a pizza place. He wants customers to be able to order online and checkout with their credit card. Anyone recommend the best way to do this, preferably with wordpress?

You are most likely going to want to start out with an eCommerce plug in and a restaurant theme from say themeforest or
wherever you choose. Next you can list his premade pizzas on the website and have normal checkout like any other item
you would buy online. Only issue now is custom order pizzas and to do this you will need to download a contact form say gravity
forms where every item you pick adds more cost to the total. The items in the check box would actually be toppings

My opinion go with a fancy and large slider to showcase his creations with a fire brick oven!

Good ideology that you have chosen the well profitable collective buying industry.For this its best to get the daily deal script from several successful web application firms which are ruling the web industries.
Companies like agriya offering Groupdeal script hope that will best for developing deal site. Just go through that,so that you can get some idea about it.