I'm a big fan of the pastukhov keyword tool.
Unless you are doing fashion trend stuff or programming or such, in most markets most keyword data doesn't change a huge amount year to year, so you can aggregate the cost of that across numerous years or such & then update once every 5 years or such. It is quite cheap through that lens. I even paid a bit more so I could leverage their db to further flesh out our free KW tool. When compared with spending a grand or two a month on data licensing from other keyword sources rolling our own through mass scrape of the Google search-based keyword tool by category back in the day & then doing a bit of fill in stuff was a good call. And now it allows us to have almost no recurring cost on maintaining our KW tool basically for free.
There has been a surprising amount of investment into the keyword tool space over the past few years.
I just came across SEMrush's new one here
https://www.semrush.com/analytics/seomagic/keywords/paydaywhich comes as part of their monthly subscription
Then there are all the Google Suggest / Google Instant result scrapers like
http://keywordtool.io/ or
https://ubersuggest.io/There is also a Firefox extension
https://keywordkeg.com/ which allows you to add Google CPC estimates to other keyword tools on the fly.
