Which is the best free word cloud generator?

If you want the words to come from a room full of people in real time, that's a different tool. Mentimeter and AhaSlides handle this. So does Slideasy.

On free plans, the thing to check is the participant cap. Most tools limit how many people can respond before you have to pay. Mentimeter caps free responses per month. Kahoot limits players. That's the limit that ruins a session, because you find out mid-presentation when half the audience can't get in.

Slideasy's free plan doesn't cap participants. You get three interactive slides per presentation and the room can be any size. The catch is that slide count. Three per presentation. If your session needs eight interactive moments, you'll hit the ceiling.

For a live audience answering from their phones, pick a tool that won't cut you off at fifty people.