Back in the day, around 2003, somebody asked me a question regarding paid search: “Do you know what the most expensive keyword is on Google Adwords, and how much it costs?”

I made a bunch of guesses, gradually increasing the amount I thought it might be acceptable to pay every time somebody clicks on an ad. £20? No? £30? Surely not!

The grand reveal was that I was horribly wrong, and that some advertisers were paying “about £70 a click” for the term ‘mesothelioma’, which is a type of cancer associated with exposure to asbestos. It was immediately apparent that legal firms would spend that kind of money because they were hunting for big ticket compensation lawsuits.

Roll forward to the present day and I wondered how things had changed, as Google’s revenues have grown to more than $67bn globally and keyword inflation is a big deal in a lot of sectors.

The good folks at SEMrush provided me with a huge list of the most expensive keywords in five countries, and for my first piece of research I’ve focused on the UK.

I had 2,000 keywords to analyse (from its database of 12m in the UK) and here are the top results…

Highlights

Gambling dominates

Betting-related terms account for 77 out of the 100 most expensive keywords, and 22 out of the top 25. How Google must wish that online gambling becomes legal in the US!

Price range

The most expensive keyword term cost £148.51, for ‘play live blackjack’. The least expensive in the top 500 cost £54.92.

Typos

Three of the top 25 target people who can’t spell ‘roulette’. Typos are regularly spotted in the top 500 results, and beyond.

Search volume

The top 500 keywords represent 217,530 searches a month. That’s more than 2.6m searches a year. Remember that the long tail is very long…

Maximum spend opportunity

As well as looking at keyword prices I calculated the maximum possible spend, by multiplying CPC prices with search volume.

There are more than 3.6m annual searches for the word ‘casino’, and with an average cost per click of £70.40 gaming firms could spend more than £27m on that term alone (assuming the impossible – a 100% click rate).

Six sectors pay the big money

As well as gambling, there are four other sectors that appear in the top 100. Companies in these categories need deep pockets to buy ads on Google. They are as follows:

Technology [10/100]

[10/100] Finance [8/100]

[8/100] Legal [3/100]

[3/100] B2B [2/100]

In the top 500 most expensive keywords we also see a couple of Health-related terms, though no mention of ‘mesothelioma’ in the UK (it remains one of the most costly keywords in the US).

Let’s look at the top keywords across these sectors…

Caveats

The SEMrush data is derived from a variety of publicly available and internal sources which makes it unique, but still very similar to authoritative sources such as Keyword Planner. The prices shown are averages. Prices paid may differ, as advertisers pay different prices at different times of the data.

Nevertheless, these prices are certainly indicative of the sums advertisers are willing to pay to attract new customers via Google.

You can download large versions of these images via EmpiricalProof.

What do you think? Any surprises? Do leave a comment below…