I prefer simple SEO techniques and ones that can be measured in some way. I have never just wanted to rank for competitive terms; I have always wanted to understand at least some of the reasons why a page ranked for these key phrases. I try to create a good user experience for humans AND search engines. If you make high-quality text content relevant and suitable for both these audiences, you’ll more than likely find success in organic listings and you might not ever need to get into the technical side of things, like redirects and search engine friendly URLs.
An SEO expert could probably use a combination of AdWords for the initial data, Google Search Console for website monitoring, and Google Analytics for internal website data. Then the SEO expert can transform and analyze the data using a BI tool. The problem for most business users is that's simply not an effective use of time and resources. These tools exist to take the manual data gathering and granular, piecemeal detective work out of SEO. It's about making a process that's core to modern business success more easily accessible to someone who isn't an SEO consultant or expert.
The self-service keyword research tools we tested all handle pricing relatively similarly, pricing by month with discounts for annual billing with most SMB-focused plans ranging in the $50-$200 per month range. Depending on how your business plans to use the tools, the way particular products delineate pricing might make more sense. KWFinder.com is the cheapest of the bunch, but it's focused squarely on ad hoc keyword and Google SERP queries, which is why the product sets quotas for keyword lookups per 24 hours at different tiers. Moz and Ahrefs price by campaigns or projects, meaning the number of websites you're tracking in the dashboard. Most of the tools also cap the number of keyword reports you can run per day. SpyFu prices a bit differently, providing unlimited data access and results but capping the number of sales leads and domain contacts.
An SEO audit should not be rushed. It simply takes time to uncover root causes of the issues affecting your online health. Depending on the size of your site, a proper audit can take anywhere from 2-6 weeks to complete. Due diligence is required when making major changes to any website, and an SEO specialist must conduct a thorough investigation to make accurate, impactful recommendations.