In the end, a figure is only as valuable as you feel it is. If you don't care about a chase because you don't like the character or the piece itself, and aren't banking on its rarity, then plain and simple it's not worth that much to you.

The opposite holds true as well. There could be an uncommon or rare figure of a character whom you love, and the sculpt is awesome, and it plays great for you; then that figure is worth a lot in your eyes. Don't ever feel ashamed about trading or selling against what everyone else thinks is right. (Of course, you also shouldn't just throw away $, like trading a chase for a common figure.)

Lastly, don't forget the inherent added value of a definite deal. Yes, you could sell a chase and in return buy a brick, but that still does NOT guarantee you'll pull the one figure you so desperately want.

If you want to do such a one-sided trade try this. Sell the chase on Ebay. Buy the fig you want on ebay. Whatever money is left you give to charity.

You would get your fig and you would be helping people. Just a thought