I would be a bit skeptical about the $40 version. That same article where that video appears says the cost is a LOT more than that.
Does Laser Rust Removal Work And Is It Affordable?
The video I saw (not the one posted) shows going directly over human fingers, no harm. Not sure I'd try that, but I'd be careful with exposure to skin, and definitely eyes.
Wow... thanks for the heads up... I could have easily gotten 'taken' on that one.