A service like BrightEdge comes with the biggest costs associated, but its SaaS solution for SEO covers many areas inside of a single ecosystem, including the ability to explore keyword data. This may be a benefit for agencies that wish to reduce redundancies across vendors, but eventually, it is likely that the need for a second tool will present itself as talent and effort levels increase inside of your SEO department.

To answer your final question, yes but not really. You can definitely use AdWord keyword planner tool to get solid organic search volume estimates. However, don’t just stop there. Leverage other tools to find longer tail variations you can map against various stages of the buyer journey. I like to use SEMrush, Keyword Tool.io and Google autosuggest.

Given you have a good idea of where to start and are fairly confident you are speaking the same language as your client, jump start research by generating related keyphrases and long tail variants with the ever so easy to use Google Autocomplete. This tool makes predictions based on what you are typing that are a reflection of Google search activity.

You can use this tool while searching for ad group ideas or keywords. Keyword planner acts like a workshop that you can use to expand existing network search network campaigns or build new ones. The tool can allow you to search for AdWords tool ideas or keywords, view the performance of a list of keywords, retrieve historic statistics, and develop a new list of keywords by multiplying many keywords lists together. A free keyword planner, AdWords tool can also assist the user in selecting a list of competitive budgets and bids that you can include in your campaigns. You can utilize keyword planner in laying the foundation of a successful online campaign whether you are a highly experienced pro or new to online. All you need is a Google AdWords account and you will be ready to sign in and get on the move.

If you are looking for keywords in languages other than English, you will find Keyword Tool's features very useful. Keyword Tool allows you to pull keywords from 192 Google domains and use 83 Google language interfaces to generate keyword suggestions. That way we make sure that the generated keywords will be relevant to the country and/or language that you are creating your content for.
The limit on manual keywords could be higher.  I personally wish we could input 10,000 keywords at a time, instead of 200.  However, I understand the costs that Long Tail Pro has to maintain each time a new manual keyword is input.  Not a deal breaker, I just wish the limit was higher. (To be fair, I don't think most keyword tools have a bulk manual option at all).