Adding Magento coupon code in (last) step of onepage checkout

Question

I have seen many extension on this matter. But I am looking for the clean, easy, close to core solution. Actually I am surprised that Magento/Ebay did not incorporate this simple win in a previous Magento release.

When a client goes directly to checkout (instead of via cart) - they are never confronted with a box to enter a coupon code. We have just launched a national ad - and the below article is true ... it is almost ridiculous how many emails we receive on this matter: "Hi, we would like to buy but cannot find where to enter the coupon code"

http://www.commandc.com/2014/01/29/top-reasons-for-cart-abandonment-2-difficulty-with-promo-codes/

Question: What is the best and most simple manner to add/integrate the coupon box in the steps of checkout.

many thanks in advance

Answer 1

So the theory: Put the box somehwhere, enter the code, fire AJAX request, code is applied. If you do it BEFORE the review step of the checkout, everything should be fine (totals). If you do it on the review step, you have to reload the review step. Then you have to deal with the JS of the review step.

If you ask me, put the box into the payment step, write an observer listening on pre_dispatch, apply the coupon code and be happy :-)