For men: A beard trimmer is one of my favorite cheap buys. Never shave again: http://www.amazon.com/Remington-MB4040-Lithium-Rechargeable-... Beyond that, I'd say the aeropress coffee maker: http://www.amazon.com/Aerobie-AeroPress-Coffee-Espresso-Make...
I have that exact trimmer. It plucks almost as many hairs as it cuts. I keep meaning to write a sardonic review of it but never get around to it.
http://www.amazon.com/Gillette-Fusion-Proglide-Power-Razor/d...