[quote author="escrowbear" date=1211324806]What is an average or typical walkaway price?</blockquote>
If your broker won't help you, ask to speak with the buyers directly. If you're early in the escrow period you should be able to explain your situation, and that there are plenty of other easier fish to catch, (excluding kaycifish) especially right now. Sooner is better than later, as they might not have made moving plans yet.
You can offer to pay for their costs so far, which might include an appraisal, the home inspection, and possibly HOA doc prep.
If it is later, you may have a tougher fight on your hands.
The good news is that your negotiating position is strong.
Request for Repairs? The answer is "No. We will not fix that."
Final walkthrough? The answer is "Between 4:30 and 4:34pm on Friday Rush Hour will be the only time it's available."
If you want to be really nasty about it, and it looks like they are going to plow through you to force the sale, you can turn the tables and ask for your own walkaway price. But that's just plain old mean.
Appeal to their reason first, and second. If that still doesn't work, kick them in the beans, then try reason again.