Small PHP code of 10 lines

Ok, Listen first, there is a plugin so that you can directly code PHP in a wordpress page. What I want is a small box saying 'Enter Coupon Code' and a space and then a submit button. The function is When someone puts '124' in the field and click submit, it will lead to the page '/page1' When someone puts 'asd' in the field and click submit, it will lead to the page '/page2' I will put the rest of the coupon codes later on, just two will be perfect for me right now. I will give you 30 mins and 2$. It is very easy task for a PHP guy and also I will give you a 5 star if you keep me headache free :)