Wordpress Plugin Coder

I am looking for someone that would be able edit a plugin I have. It is a form creating plugin that accepts payments and I need there to be a field added which can allow a user to type a coupon code in and then give a discount to the total order amount or to subtract from the cost of a specific product after selection.

If you are able to do such a thing then please send me a message with what you would charge for such a job. Looking forward to hearing from you.

Please Pm me full details ,
or add me skype : [email protected]
i can do this .

skype me , and we ll see what can be done.
details are in signature.

There are already several plugins with regular updates in the market.
You may check out before investing in one time coding as things need updates regularly in wordpress space.
One for gravity form
https://www.gravityforms.com/add-ons/coupons/