WordStream put together a look at the most expensive keywords on Bing. They did this years ago for Adwords and I imagine the results would be similar today.
No surprise the list is led by legal related names.
Now, keyword prices are going to vary a lot by position; the figures you’ll see below reflect the cost you could expect to pay per click in the top position. We grouped those 10 million keywords into niches, or categories, to give us a better idea of the most expensive types of keywords. Many top keywords within categories are close variations and you can see examples of these pricy keywords listed at the bottom of the infographic.