discounts can definitly hurt a busienss.
I was a manager at a waterpark in Palm Springs, CA and the owner decided to run a "locals" special. For the entire summer, residents of Palm Springs area could get into the waterpark for only $9.00 (as opposed to the $17.95 normally charged). It was a great promotion and we have a huge flood of new customers throughout the year.
The next year, the owner figured if it worked for just the 3 month promotion, it'll be great for the entire year - so he ran it again. And it was a success! Lots of new visitors, and it increased profit initially, until numbers were done and we found that really locals were just going TWICE in the year rather than ONCE, so the promotion was actually a wash.
So the next year, no promotion - the uproar was insane. People demanded the discount as they'd gotten it for 2 years and now refused to pay the huge rate increase (even though it was originally a discount). Locals actually boycotted the waterpark for the following 2 years until the owner was FORCED to bring back the discount.
Essentially, the owner had devalued his product by running the discount, and now people perceived the value to be $9 instead of $18.
Discounts can hurt just as much as they can help!