We've written warmly about Magnic Lights a few times before. I've run them daily for years on my main ride as my only lights: I love them. They are the lightest and most efficient battery-free bicycle lighting system ever manufactured, and a great conversation starter among even vaguely geeky types.
Unfortunately, we've had a hard time selling them, and we ordered more than a few. Many of our better bikes are already equipped with brighter generator lighting. Maybe it's because we don't court a weight-conscious clientele? Another obstacle: a pannier on the left of a rear rack will block the light: almost all our bikes have racks! Meanwhile the internet/mail order side of things is fraught with long, long phone and email discussions that we just can't sustain at the modest return on each sale: see "conversation starter," above. We're tapping out, with regrets.
We have decided to clear our stock at $100 off the normal price. All new, current production: all sales final, no remote (phone or email) support. These are still more expensive than quite bright battery lights, but far less expensive than retrofitting a hub-dynamo-based system to an existing bike. Once you get used to the convenience and reliability of dynamo lights, you just can't go back to batteries.
We've pre-assembled complete kits suitable for bikes with either cantilever posts, or caliper brakes. Got a pre-disc brake MTB or cyclocross bike as a commuter? Are you a randonneur? These can work great. If you have neither of these kinds of brakes, you'll need to order alternate mount parts from the manufacturer direct, still saving money over the normal price.
If you don't know whether you have cantilever or caliper brakes, or your wheels are not true, or you are not handy with hex keys including a 2.5 and 3mm and a phillips screwdriver, making ~1mm adjustments, these are not your lights.