A quick amazon search yields this 40W solar panel that is almost exactly equal to an iPad mini when folded: https://www.amazon.com/2026Upgrade-Efficiency-Waterproof-Lig...
Prices vary from just $40 to $80. It's certainly possible.
Those numbers are with full sunlight. You will not get those numbers in practice for most of the year in most places. First few reviews seem to say they were getting around 4 watts from the panel. I'd expect closer to 10W-12W assuming hte manufacturer is honest.
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