What I need is a simple script to direct the buyer to the correct form. A friend sells one product. To purchase the product you print out a form and fax it to him with the payment. He does not use a shopping cart. He is sending out a flyer with a promotional code on it. What he wants is a page to enter the promotional code and if it is correct it takes the person to the page with the discounted price. If they do not have the code or they enter an incorrect code then it takes them to a page with the every day price.

Can anyone point me in the right direction..