WordTree - Amazon keyword tool
This tool does not look like much from their homepage, but its super awesome inside.
First of all, it pulls data from 10 different competitor asins that you give them, as well as your own asin – to create a very good keyword list, sorted by the number of monthly searches.
Then, it has a Listing builder tool, helping you along the way to create your listing, using all the most important keywords. It even gives a few tricks, showing what other fields in the backend are indexed and you can fill them out as well.
Price: $20 per listing.
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