Back in 1994 or so, my friend helped out his buddy who worked as the IT department for a local Seattle company known as Sub Pop Records. Here's what their Web site looked like back then. Oh, and in case you were wondering, when I said that his buddy worked as the IT department, I mean that the IT department consisted of one guy, namely him. And this wasn't even his real job. His main job was as their payroll guy; he just did their IT because he happened to know a little bit about computers. (If you asked him, he'd say that his main job was as a band member in Earth.)
The mission was to make it possible for fans to buy records online. Nobody else was doing this at the time, so they had to invent it all by themselves. The natural metaphor for them was the shopping cart. You wandered through the virtual record store putting records in your basket, and then you went to check out.
The trick here is how to keep track of the user as they wander through your store. This was 1994. Cookies hadn't been invented yet, or at least if they had been invented, support for them was very erratic, and you couldn't assume that every visitor to your site is using a browser that supported them.
The solution was to encode the shopping cart state in the URL by making every link on the page include the session ID in the URL. It was crude but it got the job done.
The site went online, and soon they were taking orders from excited fans around the world. The company loved it, because they probably got to charge full price for the records (rather than losing a cut to the distributor). And my friend told me the deep dark secret of his system: "We do okay if you ask for standard shipping, but the real money is when somebody is impatient and insists on overnight shipping. Overcharging for shipping is where the real money is."
(Note: Statements about business models for a primitive online shopping site from 1994 are not necessarily accurate today.)