I'm seeing ones for around $100-120ish online.
Prebuilt units are around $60 on eBay but without the controller, and just bare panels are around $20-30.
With prices like these, I can't wait until the apocalypse. I know a couple of nearby towns that have solar panels all over the place up on telephone poles. I'll salvage as many of them as I can and have a virtually unlimited supply of energy. With all the abandoned cars around, tons of batteries to store that power.