Welcome to E-Commerce Step-by-Step. This guide is meant to show you how to build a basic online store complete with (1) a product catalog, (2) user accounts for customers, and (3) the ability for your customers to order products from your catalog.

Following tutorial explains how to create a shopping cart script with PHP and MySQL. If you have decided to design your own online store with PHP and do not know where to start, this document is right for you!

One of the key components of an e-commerce web site is credit card processing capabilities. One such credit card processing service, that is supported by PHP, is CashRegister, from CyberCash. The CashRegister service enables merchants to make financial transactions over the Internet in real-time. CashRegister works by first you (the merchant) receiving an order request from a customer and sending an authorization request to the CashRegister server. Next the CashRegister server returns either an approved or declined message back to you. If the authorization is approved the order request is completed and the customer receives their goods or services. Communications are encrypted using SSL and Triple DES at the various stages in the process.

The concept is as follows you enter some links in a database as found on the clickbank website, you add your affiliate ID and display the links on your page , you get commisions based on any leads or sales. With no further ado lets take a look at the database structure.

This tutorial is intended for PHP programmers of all levels, who wish to add Paypal functionality to their website. The programmer needs only a PHP enabled website and Paypal account.

Classes have eluded me (rather I have eluded them) since the beginning of my primitive programming days (remember Turbo C++?). They have always hovered over the horizons. This hasn't nagged me much, for I've been managing without classes pretty well, but sooner or later I had to come in contact with them. So in the morning (and I hadn't slept the entire night) I executed a gut-wrenching plunge into the depths of classes, and the shopping cart class was the first thing I wrote. Although I have made content management systems and algorithmic quote generations in PHP, I had not added a shopping cart class code to my code repository. It was not as tough as I had envisaged. I could have done something simpler but scripts like "Hello world!" seem silly after a point.

When creating a shopping cart, developers will most likely come across a number of standard problems. One of the first we had to deal with for our client's application was that of keeping "state." The cart has to keep track of what the customer has ordered as he or she moves from page to page on the Web site. That means you must be able to monitor the user's state throughout the session. Prior to PHP4 you needed an external library like PHPLIB to track state. However, PHP4 has session handling built in, so we decided to use that. (We did borrow a database class from PHPLIB, however.)

When it is time for you to start dealing with Merchant accounts, CURL is your answer to saving you a lot of money on API's and PHP Wrappers to those API's. CURL is introduced in the PHP manual as: "PHP supports libcurl, a library created by Daniel Stenberg, that allows you to connect and communicate to many different types of servers with many different types of protocols. libcurl currently supports the http, https, ftp, gopher, telnet, dict, file, and ldap protocols. libcurl also supports HTTPS certificates, HTTP POST, HTTP PUT, FTP uploading (this can also be done with PHP's ftp extension), HTTP form based upload, proxies, cookies, and user+password authentication."

Just to make sure you doesn't waste your time on this tutorial some things you need to know first. When you want to start with this tutorial you should know how to use sessions and cookies. You should also have a user system. Making a shopping cart is very easy, but always a hurdle. It's always good to set up a good plan. This because you want to make sure that it fits your costumer needs. Not everyone will need a lot of functions. Just saving, ordering and listing products is enough for most of the e-commerce websites.