It is possible that someone qualified could take this on a contingency but highly unlikely.
To have a sucessful lawsuit you need three things - a bona fide dispute or wrong, a defendant, and the defenant has to have some assets that you can get to. The broker may or may not have failed to follow instructions, the buyer may have breached your agreement, but there is a lot of work to be done to find out how to prove it and what happened, and there is no guarantee of sucess.
So if someone says they'll work for you based on getting paid at the end of this matter, I'd be concerned about their judgment. In Seattle, I'd expect to pay $5K as a fee and cost advance on this and likely $5-10K more to get it done. Hope this helps. Elizabeth Powell
I agree with Ms. Powell and this not a suitable case for a contingency fee agreement. You may want to have a talk with your broker and make a claim on the erors and omissions insurance policy, if you feel wronged. In reality your actual damages are very difficult to quantify.