Ebay is a tremendous resource for all roleplayers and roleplaying game collectors.  Books and Games that you thought were impossible to find anymore (out of print) are available with the click of a mouse!  But there are some things to keep in mind that I will cover below:

• First, check out all the options before choosing which item to buy.  Sometimes buyers get caught in a bidding frenzy and forget that they may be able to find a fixed rate (buy it now) price lower than what they are currently bidding.  Search in Ebay Stores to see what is available without bidding.
• Second, make sure to check the price you will have to pay for shipping.  It's common to find buyers who will list an item for what seems to be a cheap price only to find out that they are charging ridiculously large shipping prices.
• Next, read all the details and don't hesitate to ask questions.  If you are sensitive to cigarette smoke, or want to make sure the book has no marks or writing inside, just ask!
• Finally make sure your seller has a solid ebay reputation, feedback is more than a number, read what the comments actually say.

And now here are some tips for finding elusive books:

• Check all different variations on the same search term, for example: Dragonlance Dragon Lance, Dragon-Lance will all bring up (different) items on ebay.
• Set up favorite searches on ebay that will email you when anything matching your search term(s) is listed.
• Post on ebay's Want-it-now board, it's free!
• Search in Ebay Stores as well as for auction style listings.
• If you find a seller you trust and who carries items you are interested in, make sure you add them to your favorite sellers list.

I hope you've found this helpful in your search to complete that special book collection!