My personal experience with .biz is that few are willing to buy them anymore, unless they are major keywords. Info and ccTLDs have buried biz and us quite a bit. Serps for "gold watches" yield about 500k results, adn lots of advertising. Over a million and you can sell any extension to an end user. In this case if you can find the end user you can make possibly mid $xx, resale to a domainer at auction would be below reg fee.
Sometimes key items like this go for more, but again, more people are filtering out everything except com net org info which makes it hard for your product to get noticed.