Coupon code to be added

How do I add coupon code to the woo Commerce site I could not find the setting for it
in wordpress plugin
Also pl advise if its possible to have fields say drop down in the product page which determines the cost

im trying to sell consulting services and I need to structure price according to hours 25 Hours for 1000$ and 40 hours for 4000$ something like that
Can someone pl advise?
http://peritossolutions.com/product/test-product/