For most products like razors and other damageable items where "used" or "like new" have different meanings to different sellers, I am very careful to see everything I want to see, including reviews of the seller, before I'll bid. In fact, I have never bought a razor on the 'bay, but have bought some other rare items (propeller for an old gas powered model airplane).

I think forums are best marketplace for most items like razors and handgun parts (my other obsession), where you can be sure the seller knows what they have, are known to a community of like-minded enthusiasts, and don't want to be outed as a cheat, liar or fraud in that community.