This weekend only... 14-16 August...
Harbor Freight Tools is selling their $250 3-panel 45W solar panel kit for $169.99.
The kit includes: 3 15W solar panels, charge controller with LED indicators, two 12v
compact florescent lights, and mounting hardware.
While 45W is not enough for comfortable boondocking, it IS enough to always keep your batteries at full charge when your Airstream is idled, and with light use can keep them well maintained during short trips or time away from AC power. It's a handy addition, considering this weekend only, it's $170!
(I am not in any way affiliated with Harbor Freight)