I just ran across the same thing. Tesla quotes a little under 30k for a 12kWH system, which seems pretty fair/honest. But I also got a quote from some other com

I just ran across the same thing. Tesla quotes a little under 30k for a 12kWH system, which seems pretty fair/honest. But I also got a quote from some other company and they wanted 70k for a 9.6kWH system. How can you have a 40k difference for a worse system? I actually think it's because the economics of solar are, in fact, really good. Plus there's a 26% (or something) national tax rebate if you install solar right now. That's a straight up rebate (cash in pocket), not an income credit. Because things are good, there's lots of wiggle room for people be taken advantage of. I don't really know how to details work out but when you get "solar loan" financing involved a lot of weird stuff happens. All of a sudden you can afford a 60k loan every month because it's basically what you pay during peak usage anyway, and the loan hides in the value of the house when you sell it, and why not get some instant cash from the government rebate? It doesn't matter that the system only actually costs 12k to install. You paid 60k and that's what the government knows and future buyers won't even question it because it's like a $40 difference on their mortgage payment. Everyone in the middle gets a cut, the company profits, the sales rep gets commission, you get a rebate and future homeowners get the bill, nice! I don't even think it's necessarily nefarious. There's just a lot of room once you're going to finance something. I'd recommend cutting out the middlemen. Go straight to the source. Or just buy the hardware and talk to a roofing company and electrician.