Benchmark lending was something I had never heard of. I did some research, and found it has to do with interest rates and banking, which seems to be a popular theme among high paying keywords. The benchmark rate is set by the Federal Reserve in the United States, and it is the interest rate the banks pay when they borrow money. That's right, your bank borrows money, too!
They must have a certain amount of money on reserve, and when they don't they borrow money over a very short term (such as one night). So why is this term so valuable? Banks and mortgage companies seek out people who might need a loan. Banking makes it's money on loans, it's just a valuable business to be a part of when there are lots of customers. This price seems almost reasonable compared to many of the other keywords.
This page of Benchmark Lending information is intended to show you why it is a high paying keyword, so you might be able to understand what you'll need to know to make a website centered around it. Other sites just give you a list, I am just trying to explain why each keyword is on those lists. I do not claim to be a Benchmark Lending expert, and I encourage you to do your own research. The price for each keyword comes from a variety of high paying keyword lists, and I do not guarantee it is accurate at the time of your visit.