the tesla lithium stores 14 kwh. LG, Mercedes, BMW, and a few others are making battery banks too. The range from 5 kwh to 25 kwh and $3k to $25k installed.
I have not been able to find actual wattage per sq ft on the tesla roof tiles yet, but found that it's %25 less than current panels. Once Tesla's new gigafactory is in full production the prices will drop. It's still smart to wait a year. I just patched a hole in my roof so I could wait it out.