i want to see if these \"build a . . .\" flash sites (to support a user customized ordering process) are done using regular flash or Flex?
Hm, I still don't really like any of the answers, so I'm going to chime in.
First question is "What's the difference between Flash and Flex?". At their core, they're one of the same. There is some confusion between Flash the platform (Flash Player) and Flash the tool (Flash CS); there's also Flash Builder which is a development environment made to develop in pure Actionscript or Flex. The Flash Player uses Actionscript to display what you need or you can use Flash CS to create visually what you want to show. In my opinion, don't use Flash CS unless you need a drawing/animation tool (which I don't think you do). With that said, the real question should be "What's the difference between Actionscript and Flex"? Well, there is none from a technical standpoint since Flex is made with Actionscript. What matters here is that Flex is a framework that's made for rapid rich internet application implementation. It uses the concept of layouts, skinning and styling as well as standard components (buttons, comboboxes, labels, datagrids, etc) to help you create striking applications easily and quickly. You could do the same thing in Actionscript, but would take you longer to implement the same thing, however the end application would be a lot leaner and quicker to download (normally).
Second question is "Should I be used Flex or Actionscript to create my ordering wizard?" which is the one I think you should really concentrate on. The answer is "it depends on your requirements". What Flex is really good at is a clear and concise codebase using development tools meant for user interfaces. If your ordering wizard is going to be fairly complex and/or data driven you should probably use Flex since it will give you tools to create it faster as well as make it easily changeable later. However, if the wizard is very simple and just needs to be implemented once, there's no reason why you can't use Actionscript to do it.
I hope this was helpful.