You can also get cheaper batteries and larger panels off Craigslist for much less. You can easily find much larger panels for around $100.00 - same kind you see on roofs. Batteries are more difficult to find cheap, but 6 volt golf cart batteries are readily available and low cost. Sometimes you can also find the 12V 35 AH wheelchair batteries (same as what the author used) cheaply too.

Point being, if you look around, solar electric generation at a small scale can be done even cheaper than purchasing off Amazon for some of the components (inverters and charge controllers are mostly exempt - unless you go to a hamfest).