You have to enter it before you get to the Paypal page. Go back to the order on your Etsy cart and you should see a small box with something like ''this seller sent you a coupon''. Check the box and the coupon will be applied.
If you don't see the small box with the blurb, click on the bell (deals) and/or heart (favorites) icons and the offer and code should be on one of the lists. You can apply it from there.
