I think the secret unofficial numbers in the personal finance blogosphere is $1-7 eCPM ... so if you have 100k views per month, you'd be making somewhere between $100 and $700/month. There are outliers to this.
If you're in the "jokes about dogs"-blogosphere, the numbers are less. PF is one of the best paid niches. [My advice if you want to make money is to stay away from frugality. Focus on "getting out of debt"... your natural readers will be self-selected spenders---as they've managed to spend beyond their means in the past, they likely are impulsive and so they will click on your ads, etc. Cynical maybe ... but that's how the blogging business works.]
In general, the more you treat it like a business, the more you'll make, and the more boring your SEO'ed keyword filled writings will appear. You'll be the online equivalent of a magazine---funded by ads, offending none, presenting the same things on an annual rotation. How many blogs did a superbowl post?
To wit, as long as your writing is good enough, it depends on your self-promotion skills. For example, is the 4HWW great writing or even original? Well, the answer is no to both questions but since it's so well promoted it is the first thing people who don't know any better reads, and there you have it. Indeed if you can expand a niche into virgin territory you can make it huge.
Now, realize that blogging is a rockstar profession. A few people (usually the first) make most of the money(*) and the rest make $100/month. The easy money was made 10 years ago. Back then, you started a blog and since there were few around, everyone who started a blog after you linked to you and so on. Hence, today some blogs are incredibly well linked although they're kinda boring. It's not exactly a level playing field. It's the Matthew-effect of blog-networking. The well-linked get more well-linked. I even enjoy some of that effect myself... why do I keep getting traffic despite not having written much since 2010? Because people have linked to me in the past.
(*) And you might be surprised how many top blogs are actually owned by venture capital companies who have bought out the blogger. And how some bloggers actively pursue this strategy, e.g. start ten blogs, crosslink them heavily and then sell them once they've reached a pagerank of 3.
If you really want to write for money, associated content, helium and the likes offer more bang for the buck. You get paid upfront. Of course if you want to make serious money doing this, you need to be able to tolerate the braindamage that would normally opbtain from writing 50 articles [with slight variations] on how to recycle beer cans in order to provide the content for some blog-flipping entrepreneur who hopes to sell his site that has good keywords for beer, can, and recycling.
