Keyword research tools can cost as little as nothing or as much as several hundred dollars.

Although many small businesses understand the importance of keyword density in their online strategic planning, most don’t have a few hundred dollars set aside for such tools. There’s no need to sacrifice quality SEO due to lack of funds. To help, here are five of the most commonly used keyword density tools that will give you the biggest bang for your buck, for under $100 per month:

Please note that, with any online tool, each has its own features and keyword density tools should not be compared by price alone. Find what works best for you, your company and its online goals.