Really Cheap LED Lights For Bottle Dynamo Systems?
 

I look after the bikes of my friend and his daughter. They have bottle (sidewall) dynamos with old incandescent headlights and taillights. The lights are really quite dim. I'd like to to replace them with brighter LED lights, as a favor. I don't want to spend much at all. Has anyone found a cheap Chinese LED light set that will work with old bottle dynamos? Like, for $20-30 the set?

Cheapest dyno LED headlamp I'm aware of is the PlanetBike Blaze Dyno, I've seen them on ebay for under $40:
Blaze Dynamo