Here are some AI-powered tools and sites to create motion videos for free:

Free Options
1. Animaker: Offers a free plan with limited features and watermarks.
2. Renderforest: Provides a free plan with limited features and watermarks.
3. Powtoon: Offers a free trial, and a limited free plan.
4. GoAnimate (now known as Vyond): Offers a free trial, and a limited free plan.
5. Raw Shorts: Offers a free trial, and a limited free plan.

AI-Powered Tools
1. Lumen5: Uses AI to create animated videos from text content.
2. InVideo: Offers AI-powered video creation with templates and effects.
3. Wibbitz: Uses AI to create short-form videos from text content.

Online Video Editors
1. WeVideo: Offers a free plan with limited features.
2. Shotcut: A free, open-source video editor.
3. Blender: A free, open-source 3D creation software.

Limitations
Free plans often come with limitations, such as:

- Watermarks
- Limited features
- Limited video length
- Limited export options

Be sure to review each tool's terms and conditions before use.