My clients seem to love coupon and promo codes, but I've recently become very skeptical of them. When I'm shopping there's times I'll see a promo code field and I'll wonder off to other sites to find them. If I can't find any I feel like I'm not being treated fairly, it's not fair that if I know some secret password I could save $10 bucks. There has also been times I've just completely forgotten that I started to checkout and I never completed the order because I got distracted. I asked a few friends about this and they all say the same thing happens with them.
I'm wondering if I should just apply the codes automatically or maybe just create special urls the user can enter the site with that automatically apply the codes so others just don't see the field.
Anyone ever run any A/B testing on this? My clients don't want to part with their promo codes but I'd love to cite some real world examples. I don't think they realize that not everyone will have a promo code.