I have looked through all the Astra themes both free and premium, and there is so little shown on the website that the information shown is very insufficient to make a choice.
The choice is based on what are you trying to do. Astra is a multipurpose theme and basically means that you can build it as you want using a page builder.
You can start with the free version, play a little and then choose.
And something that most people do wrong is that they seek for a theme that has everything and does everything many plugins. If you have some skills or you want to learn, go with a simpler theme cause the overload themes are heavier. When you look for a theme also check the changelog. See how often it gets updates. Check the support. Make a question and see how long they will take to answer back. Don't just look pretty demos and nice pictures.