Nobody is compelled to use the BC marketplace, eBay, Gumtree or even the classified pages of the local rag (if it still exists). If you have something to sell, it's up to you to find the best channel through which to move it on. You may well have to accept less than you consider it worth in order to do so. That's just good old market forces at work (the same market forces that work to your advantage when you buy something for a bargain price, remember). If you don't like it, that's just life, I'm afraid. If you're buying, caveat emptor is as valid a motto as it ever was.