Then buy the things that are marked "New" or "still sealed". I have had very good good experiences with ebay, many games were in good to very good condition (if not new).
If you don't accept this - then good luck in finding WCP Gold, new and for less than 20$
There are lots of people who earn their living off eBay. They cannot screw people, because if they start getting too much negative feedback, they're out of business.
Not only does Gold include the complete SO, it also has a new, expanded manual, with stats for all the ships and other goodies that were somewhat lacking in the original WCP manual.