Like mentioned before ebay is a good source. I got 2 of the 45 watt solar systems from
Solar - Harbor Freight Tools
When it was on sale for $140. Comes with panels, charge controller mounting bracket and cfl lights. May not be the best source if your not in the U.S.
Here is a way to increase solar power output by 20-30%.
A Simple DIY Solar Tracker - Hack a Day