Keyword research is the basis of your PPC campaigns and this list of precious terms will largely decide the success of your paid ads strategy. You can’t generate a kick-ass keyword list without regular, thorough research though – and once your brain is fresh out of ideas you’ll need a helping hand or two.

Luckily, there’s a huge number of keyword tools out there to help you research and refine your list. The only trouble is there are too many to choose from, which is why we’ve put this list together of the best free tools to discover kick-ass keywords.

Google Keyword Planner
All you need to use Google’s own Keyword Planner is an AdWords account and, although it’s not as insightful as its previous Keyword Tool, it’s still the definitive choice for many marketers – and with good reason too.

WordStream’s Keyword Tool
WordStream’s keyword tool isn’t strictly free – despite what it says – because you only get 30 free searches before you have to pay for its services. That said, these 30 searches return more keywords, faster than the same number of searches with any other tools we can think of. This alone makes the free version of WordStream’s keyword tool a must-have for any PPC plan.

Don’t worry, we’re not exactly sure how to pronounce this one either – but there’s no doubting its use as a keyword tool. Enter any phrase into the Soovle search bar and you get suggestions from Google, Bing, YouTube, Yahoo!, Amazon and other search orientated platforms as you type.

Ubersuggest is possibly the ultimate free keyword tool for when you get a mind blank. Type in a key phrase and it returns an almost endless list of variations in alphabetical order – ideal for when you can’t think of a single new keyword.

Keyword Eye
Keyword Eye just about makes it onto our free list because its free version offers enough to bolster your PPC efforts without asking for a penny. You only get 10 keyword searches per day, but you can search every day and you get Google, Amazon and YouTube keyword tools included – while the £9.99/month pro version brings more features limitless search to the table.

Next time we look at paid keyword tools
The free keyword tools in this list area great assets to any PPC campaign, but sometimes you want to pay up for something a little more extensive – so next time we’ll take a look at the best paid tools to discover killer keywords.