I bought a cheapo £15 one from Robert Dyaz, it's decent for the money and my room isn't really big enough for a huge fan. I struggle to sleep while there's noise of certain decibel levels though, unless I'm drunk then i'll just pass out. Also I swear my fan gets slightly louder the longer it's on but I don't know if I'm just imagining that or not.
I've got this, and it's pretty bloody loud. But because it's a constant drone, I don't find it too difficult to sleep with it on.
Are you me? I did exactly the same thing a 3 weeks ago, save for the fan being from Amazon. I wish mine was quieter too, then I could have it on while sleeping but it's too noisy unfortunately.