They're right. With few exceptions. People just aren't buying stuff, especially collectibles.
Sometimes the best value for something is not money, but something of more value. Recently I was able to trade a couple of old (and valuable in a good economy) bottles for a really nice sailboat. Here's a picture:
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You can read more about this deal here and maybe it will give you some ideas for how you can get really great value for your collectibles.
Mike