You know  social media can be a great source of insight about what your  customers and others think about you or your company, about what people are most interested in and worried about, and about new trends you can take advantage of before your less nimble competitors catch on.

But how do you capture that information quickly enough to do something about it? Especially when social media presents a constant flow of ever-changing information? You need software to help. And, while there are a lot of expensive options out there that big brands use to track mentions and complaints, there are plenty of great options that don't cost a cent, according to Dylan Echter, social media specialist at Capterra, which helps businesses review and select the software that best fits their needs.

"While advanced analytics are available in many paid social media monitoring platforms, small business owners--or anyone looking for some additional insight--can use free tools to get a sense of what people are saying on social media," he explains. Here are the ones he's found most effective:

1. Hootsuite

Hootsuite (like Tweetdeck, below) is handy for its ability to "create custom live feeds of posts that allow you to monitor a brand, profile, or search term in real time," Echter says. "These feeds are one of the easiest ways to monitor what is being said, then reply or resolve the issue as quickly as possible. They use modified Boolean operatives to discover new posts, allowing you to be fairly specific with what it is you're trying to monitor."

For instance, he says, you can set a feed to search for posts containing your company name and a negative sentiment, posts sent by or mentioning a specific profile, or even posts containing a search term and asking a question. If your company sells sewing patterns and supplies online, you might want to flag posts containing a question and the terms "sewing pattern" or "cotton thread," for example. Hootsuite's home page makes it appear that you can only get a free trial for 30 days, but in fact the service does offer a free level.

2. TweetDeck

TweetDeck offers many of the same features as Hootsuite, Echter says. The catch is that, since the company was acquired by Twitter, it only works with Twitter and no longer with other platforms such as Facebook. But some companies and industries are very Twitter-driven and if that's your case, Tweetdeck is worth considering, Echter says. "Of the two, it's the quicker tool."

3. Social Mention

Enter a term into Social Mention and the service will let you see mentions for that term across a variety of social networks and blogs. It allows you to see whether those mentions are positive, negative, or neutral, how often the term is mentioned, corresponding terms, top social profiles mentioning the term and the passion and reach of those mentions, Echter says. "As a start, I recommend you search for mentions of your brand and a few of your competitors to benchmark the size and sentiment of your social footprint."

4. Hashtagify

"Hashtagify allows you to discover the most popular and most frequently used hashtags related to a specific topic," Echter says. "When you search for hashtags related to a topic, Hashtagify will show you related hashtags (showing both correlation between tags and which ones are most frequently used), as well as the top influencers for that topic." This is a very handy way to find out which hashtags you should use to give your tweets and other messages the most reach, as well as to find out what topics or issues are of most interest to your audience.

5. SocialOomph

"While SocialOomph has a well-rounded paid version, its free version lets you set up alerts for Twitter hashtags," Echter says. It gives you all the tweets containing a keyword or hashtag, in one place he says. Best of all, you don't have to keep checking the service--it will email a report of recent tweets.