I've been waffling on the subject of buying one for a while, and now that I've finally decided to I have option paralysis--there are a huge amount of places that make or sell them (generally online), ranging from suspiciously cheap to far too expensive.

I was wondering if any more experienced anons could point me in the right direction?

I'm looking for something that's:
-around 5-7" long, unsure on girth
-quiet (I have several housemates)
-preferably vibrates
-preferably waterproof
-preferably has a suction cup or other mount for walls/floors and so on.
-quiet (cannot stress this enough--especially if it's on a wall or floor!!!)