The best way to appraise your items is to see what items have actually sold for recently on eBay. Make sure you are logged in to eBay, then enter a search query for an item like "Players handbook" and then check the little box on the left hand side that says "sold listings." For me, that gave me quite a few items, and some of which are sales of items you are selling. Add more terms to refine your search. When evaluating these sold listings, you have to factor in shipping, condition, completeness and many other factors which can affect a final sales price. You may notice that very similar items sell for very different prices, so unless there are three or more sales, you still may not know with much confidence of what an item would really sell for. By using this process, you'll be able to evaluate most, if not all, of your items for sale. Then, if there are several items that have you stumped, I'd come back and request more specific advice.
Truth is worth finding and life is too short to work for money.
