PHP Website with simple stock control and membership

I will need to develop a system which consist 3 Interfaces. One interface is for Cashier, one is admin, and one is user. Rough Description: Admin - Create Manage Edit User - Create Manage Edit Stock - Sales Report Cashier - Key in items sale and reduce stock level, add to sales report User - Can login to check stock level - Request to change price - Check Sales Report ****IMPORTANT: Most important thing is security here, besides design, security is really important, you can't just really use login module to plugin the code. Yes, just these few php pages. One login page with 3 user type to choose. Layout is drawn, just some color and theme for. Detailed layout will be sent if I am satisfy with your bid. So BID AS LOW AS you could go, if after I sent you document and you can't provide with that price, then you could raise up. The reason for your to bid lowest price is that I will contact the lowest and move to higher one, of course your portfolio is important, so please get your portfolio ready. Thanks.