Therein lies the only problem (well, the only real problem). It can take a lot of effort (and sometimes money) to determine what is worth selling, or should head for the landfill. This is why it’s good to know a thing or two about doing your own appraisals. Now, keep in mind that this will not necessarily be as accurate as going to an actual professional, but it can give you some good guidance.
First, the best place to look is online. What you’re going to try to do is to find the same item that you have in your possession and see how much other people are selling it for. This will give you a good idea of the expected value. Sites like ebay and amazon are great for this sort of thing. Finding any defining markings or labels on the item is a must here, as there is a sea of other, similar stuff to be found.
Another thing you can do is to visit a local pawn shop. My local Hollywood pawn shop had items similar to what I was trying to sell, and they gave me a good idea of the value. You may even decide to sell it right then and there to avoid the future hassle of finding a buyer later on.
Finally, there is professional appraisal. This can cost you, so only do it if you really suspect that you have a really valuable item on your hands.