Nobody wants to appraise because of the .bz extension. If they were a .com, you would be a millionaire most likely. Instead, you bought a Ford Pinto. Remember those? Probably not. I bought www.News.bz in the past , thinking the same thing. IT HAS TO BE A WIINER. It had something like 2 billion on Google. Sold it for $200.
A .bz is just not that popular, and sorry to say, I don't think they ever will be.
Great keywords. Low $XXX, if you can find the right end user. But, since you already bought them, you may as well hang on to them for a year, or two, and see if that end user will find you.