You can find a comparison of Google's smart displays and their costs here:
They have built-in speakers, so you don't need to buy ones separately and the hub itself is the brains.
Sorry for the late reply. I wanted to check in and see if you managed to see davidking post? Please let me know if you are still having trouble, as I would be happy to assist.
I want to ensure you are good to go, and everything is working properly. Please let me know if you are still having trouble, as I will be locking the thread in 24 hours due to inactivity.