Breaking the grip

I'm a hard working businessman who want to provide great customer service to my future customers with the goal of having repeat business from them and their friends and family. I would like a web site that allow customers to order from my site and have them enter a discount code the is exclusive to a sales agent that made the sale and have it count towards that salesperson/individual as a monetary credit and then have that deducted from there over all purchase. I would like to give the buyer the option to purchase a extended warranty plan that can be applied to the initial purchase or can be billed on a monthly basis.