This article gives an idea of how much a Tesla PowerWall will cost.
This StorEn company has only a few employees. They are crowdfunding and have not yet sold a flow battery. They’re supposedly in the business of making vanadium redox flow batteries.
https://cleantechnica.com/2020/10/05/tesla-megapack-powerpack-powerwall-battery-storage-prices/
Update Feb 23 – TSLA was down to $632 a share, from well over 800 earlier. Looks like it’s time to buy some more.