You're missing the real value of Shopster. Don't use them to setup your drop shipping business - use them to test your ideas before you invest alot of time and money setting up your real site.
Use Shopster with a generic domain name (something like beststuff.com, greatdeals.com, etc.). Now when you have an idea of a new site, fill you Shopster store with those products. Sure, their not as cheap as you can get them elsewhere - who cares. All you want to do right now it test the market. Drive some traffic to your Shopster store and see if it converts. Play with pricing to see at what levels people will actually buy.
If you break even on a Shopster store, you know you can be very profitable with a full blown store - so then invest the time and money to set it up.
Rinse and repeat.