How can I use google app engine?
You can build almost anything on GAE. As Monk would say that is a blessing and a curse. GAE is relatively new and so e commerce ventures are relatively rare. This means you would be responsible for every piece of the site. Other dedicated e commerce technologies trade some of the control and look and feel for ease of use/setup. 
So in short yes you could use GAE to create an e commerce site, but you would be spending a lot of time getting it up and running and then managing it. Time you may find better spent on sales and marketing.
I've begun planning a kind of web store interface that I want to work on soon. I'm starting to import products from China and want to have a completely unique feel for my site. Now I'm kinda a google fanboy and have heard alot about google app engine. Mostly I like the hosting available with google more then anything though. But I wanted to know, would the App Engine be good for what I'm making?
Namely a web store with an app like feel. I've decided, to help if I ever need to move my host, to work in web2py hosted in the App Engine. Or would I be better with django or something on a normal host? 
Is google best for webapps? Or is it pretty well suited for webstores as well?
Thanks