Hi guys, i finally went with Gift Certificates, i got a feeling that discount coupons aren't the one i am after. Well i created a new field in product adding page for the gv_amount where admin can specify Then showed it in product display page, to cart and checkout page; also had to modify them to show in orders page in admin side, customer my account and also the emails. Also i had make sure that Gift certificates cannot be bought with gift certificates. Done this at payment page
Also removed sending redemption code to customers.
Took some time about 2 weeks to do all these, finally project completed and delivered to client.

Many Thanks for all your help and support