I've had my eye on this panels - http://www.amazon.com/RENOGY-Monocrystalline-Photovoltaic-Battery-Charging/dp/B009Z6CW7O/ref=pd_sbs_lg_1?ie=UTF8&refRID=14XDRTDJ4GZX54S09VFJ

Might be overkill for your needs and you'd have to add a battery and charge controller (I hear the MPPT ones are good), but this seems like a decent deal.

I bought a Renogy 100 Watts 12 Volt Monocrystalline Solar Panel on Amazon in 2017 for $140 for my tiny camper. I mounted it to keep it safe and secure, but I could have tossed it in the truck and plugged it in when I needed it. Its not super fragile, but some sort of homemade case would be nice. They are cheaper and smaller now and you can go cheaper if you get the polycrystalline.

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This is the panel I got https://www.amazon.com/gp/product/B009Z6CW7O

But here is the newer version for $105 https://www.amazon.com/dp/B07Q6L8HQ9/

Ya you need a charge controller too, but that ranges from $30 to $150