Done summat a bit more involved for mine, got an old but usable car battery (free), two solar panel trickle chargers (£10 each Maplins), a 300w invertor (£20, i think, Maplins), several (9 exactly, but only used 3 so far of each) low energy bulbs (9w and 11w, 50p each Netto) and ceiling roses (£1, i think, B&Q) and rigged them up together. In the depths of winter I get a couple of hours of light from them, the rest of the year there's more than enough and sufficient left over for a bench grinder.
If it gets too flat it's up home with the battery and a couple of hours charge.
To be fair I would prefer a bigger solar panel, which would allow all 9 bulbs but it just about suffices for me. The shed/garage is about 20x25ft, and 3 bulbs gives a good workable light.
I would imagine that this is much brighter than the shop bought solar lights.
