Why is PollEverywhere my hands-down personal favorite polling tool? Because the students can text in their responses from their cellphones. No more response systems, with their added hardware and software, necessary for the classroom! Very millennial . . .

You can use PollEverywhere for free, but there are certain limitations. With the basic account:

• You can have at most 30 respondents. I don't know about you, but my classes typically have more students than this. I upgraded to the $10 per month plan, so that I could have 50 respondents.
• You don't get individualized data. This is OK if you want to assess the general level of understanding of the class, but if you want specific results for each respondent, you'll want to upgrade.