Yes, Pixc: AI Auto Alt Text has a free plan, so you can use the app at no cost.
The Free plan includes 25 image optimizations per month and gives you access to both AI mode and Template mode, skips existing alt text, and allows you to override and edit generated alt text.
When you install the app, it automatically analyzes your store and shows the current alt text of your images. Nothing is changed until you click the “Generate Alt Text” button, so you’re always in control.
Need more than 25 images a month? You can upgrade to a paid plan anytime.