The Waterpik Cordless Plus Water Flosser is a great product, which lists for $50 and usually costs about $40. For that price, though, you aren’t buying it: you’re renting it. That’s what Jeff found out when he bought one. The rechargeable battery stopped working just past the warranty expiration date. He bought another: maybe that was a fluke. The new toothbrush lasted a whole 13 months. [More]