99lessbuy.com

I want to build an online store like [login to view URL] where I have seller's account, customer account and admin interface. for seller interface, it gives reports graphically as well as non-graphically to them about there sales of the product they are selling. for customers, it should have customer account, delivery addresses(upto5) and details like credit card which we can store, so that next time they don't have to put the details again. If there are crawling website for a particular product, then we should send mail to them that you were interested in this project and want to buy. for admin, one seller submits to sell particular product online, it will display only on website once it's confirmed by the admin interface. at admin interface, we should have mechanism to send mails to all registerted users for discounts, new products launch etc. It should have tracking system as well. It should send mail or sms to user about the product he bought online. So I want to build online store based on above feature which can be more once we start working together. First in initial phase, I want to know the high level design of the website that website will do and features of the website. Please let me know the technology will be used. In second phase, needs low level design, what are requirement of the server for at least 1 lacs customer account and 1000 seller account and around 10-20 admin accounts. one should be root account. How many users can crawl website at a time, I need stress testing of the product during testing. There might be more things as well, once we start working, we will come to know about it.