Can you also make 1 coupon for both the products and shipping?

Please note that on the payment fields, only one coupon code can be applied.

But there is a workaround where you can add the products outside the payment fields along with the coupon codes. You can then pass on the total amount to the payment field - https://www.jotform.com/help/275-How-to-Pass-a-Calculation-to-a-Payment-Field 

Please check this related thread for a suitable workaround - https://www.jotform.com/answers/1772143-How-to-use-multiple-coupon-codes 

Do give it a try and let us know if this works out for you.