If you need 12V out...
You can find a cheap monocrystalline panel and directly hook the output into the input of a battery pack:
This is a good 5W mono panel (small 8.7" x 10.4" about a sheet of paper) and is a good deal at $30. Ask about connection wiring before you buy.
This is twice the power--10W--for about half the price but bigger.
This 8000 mAh power pack has an input up to 19V so the panel can charge it directly. It has 9-12V output (for your cig socket), USB for phones etc, and 16-20V output for laptop computers. The trick with this power pack is, people are using it without a charge controller because it's apparently built in. I'd put a diode between the panel and the battery so you don't lose current backing up into the panel when it's dark...or just unplug the battery when you aren't charging it. Easy peasy.
That's all you need--a 12v solar panel, an Energizer pack, a bit of wiring, and the cables to plug your devices into it. It might all fit into a large single revolver pistol case or jerry-rig something out of tupperware.