Build a Web-to-Print Service with Shopping Cart

I work with a printing and mailing company and we are trying to help an insurance company get set up online to offer mailing pieces to their distributors. They already have a website and they even have a developer that they work with regularly. However, I need a bid for building a piece of the website to take care of their ordering - basically a web to print service with a shopping cart. (The site is a basic HTML site, not on a CMS or anything.) The process is as follows: (1) Agent will log into the website and be able to click on a "LEADS" button. This will take them to the next page (that we get to create) which will have a brief explanation of how the system works, why they should do it, etc. It will also need to have the three mailers (possibility for adding more pieces) that they can choose from - so they need to be able to see the three options and then click on a "VIEW MAILER" and have it pop up either within that same window or not, (whatever is easiest). They can then select that mailer and click "CONTINUE" (2) This will take them into the mailing list portion which is supposed to be a plug n play type of thing. Once they get their list selected they'll click okay or continue and it will take them into the next part which we create. (3) Each agent will be able to select a mailing list of a minimum of 2500 names (they cannot order fewer than that). (4) Once they get to the shopping cart, it will have a basic unit price per name and will figure their total from there. They will only be able to order ONE MAILER per transaction so it's a really REALLY simple cart in that respect. However, they have a certain group of agents that they want to charge about half as much as the others. So we need to either a) have a place for a code that allows them 50% off or b) be able to use their username as a way to change that unit price...They'd prefer it that way but I don't know what's possible. We do needan option to enter a coupon code and have a user friendly way that they can enter the coupons in each month. I need this done in 2 weeks time. Let me know if you have questions.