Potential Paths: Path 1: The teacher could use Gamma, which offers an AI-powered text and design feature and a free plan, albeit with limited AI credits. However, users have found the AI and design features to be very useful in creating engaging presentations. Path 2: Alternatively, the teacher can try out Decktopus, which also has AI functionalities and a free plan with limited features. Teachers could avail a discount on the PRO Plan, although some users have reported running out of AI credits quickly with this option.

Final Narrative: Finding a presentation software that includes AI-powered design capabilities and is free of cost can enhance your teaching experience and help engage students better. A tool that could fit your requirements effectively is Gamma.

Gamma is a web-based tool that uses Artificial Intelligence for helping you create presentations, memos, and documents. It even suggests graphics and text for your slides. What makes it suitable for your requirement is that it offers a free plan. In the free plan, the key features such as AI-Powered Text and Design, Customizable Templates, Widgets and Collaboration are all included.

However, it's important to consider that the free plan has a limit on AI credits and they don't refresh every month. Nevertheless, for optimally utilising Gamma within this constraint, you could start by entering your content and letting the tool suggest design elements. If you're not satisfied with the initial design, you can customize the slides with different colors, fonts, and themes. You can also add videos, gifs, charts, or websites to your slides to make your point clearer. To make the process more collaborative, you could also invite your team to work on the same presentation and give immediate feedback.

So, with careful and efficient usage of the AI credits, Gamma's free version could potentially fulfil your needs of creating AI-powered, clear, visually appealing presentations at no cost.