It depends.<p>On an older site I ran we discovered the same thing and exploited it. We made it easy to find coupons for our product via Google. Interested visitors would land on our buy page, see the coupon field, search Google, find one and buy the product because they felt like they were getting a great deal. The conversion rate went up. The original price took in to account a lot of users would be using a discount. We split tested having the field and not, and we made more money with the coupon code field and giving out a lot of coupons.<p>Yes, some users that would have paid full price may take advantage of the discount. But, potentially, you will get a lot of customers that only buy because they find a discount. My guess is that this works better for lower cost "consumer" type purchases (not larger, business purchases).<p>Making coupons / discounts easy to find is a marketing strategy. Why do you think half the apps in the app stores have "Limited time discount offer!" as the first line of their description.