solar panal

This is a good panel size as a maintainer for your car battery in storage. To prevent it from self-discharging during long absence. But you will have to cover the controller block from rain. Small kits are more expensive per watt than big panels, so this comparison doesn't work here. As a car battery maintainer "kit", with cables and all, this is reasonable price.

For anything else it would be useless. Camping-size solar should be at least 60W for a tent-style living.