Ebay is risky, if its uner £15 its probably ripped off and you'll get problems. Recently, someone on here told us that they needed a new "language bank" (a folder that is in FPSC) because his version was in french; it was probably ripped off.
You've got to remember that Ebay and Amazon will usually only sell new and used products and therefore you can't garentee (sp?) what the contents are like. Also, they won't sell the model packs becuase they're downloads so without pirating them, you're gonna have to get them from the game creators.
My advice: Buy from the game creators
AE