DB user creation and product selection based enquiry submission

I require functionality to be added to a site in order that site visitors can create a user ID and Password ( Account. ) The site is currently in development. Once logged in they will have the ability to select products from a portfolio view and selected items to be stored in a viewable "Lightbox" or "Visual Cart". ( not lightbox script ). This will be similar to a normal e-commerce store but there will be no payment processing nor any need for related security. It is simply being used to generate trade inquiries based on items selected. ( There are a total of 100 possible items broken down into 5 or so categories ). Each image will have price and a small description. Image is very important to my client and the end result must be quite slick and unobtrusive.