I've had unpleasant experiences with cheap crank radio/flashlight combos. I have one that has failed sitting in the drawer with no use for several months - I crank it for two minutes, and the lights come on but the radio no longer plays.

This is one of those things that we get to make a judgment on: many things can be cheap crap and get us by, but some things we need to have working when we need it. It may be that a radio is something we can get by without. If so, I'd buy a few cheap ones with solar panels and cranks and such. But if we're going to really need the radio, I'd buy a good one from a known manufacturer that provides a warranty. (Not that the warranty will do me any good, but if the maker provides one, I'll expect some reliability.)

I like the idea from another poster about using a stand-alone solar panel to provide charges to real batteries. I have such a panel, and I'll do just that. I have radios that run on AAs, and I have a AA charger.