The best value-for-money silent ventilation?

My war with noise has been going on for two months, and I've realised that my ventilators are just basically shit. I was wondering if anybody can recommend good quality, silent ventilators preferably below £20 line... I realise its asking too much, so if not silent then at least sturdy ventilators tha can handle the appropriate modifications for stealth (such as placing them in an acoustic box), which i've realised to my dismay my own vents are too shit to cope with...

I would use an inline fan(A fan desinged to go inside ducting). Attach ducting to both sides. Then cover the fan with a Water Heater "blanket" or fiberglass insulation covered in plastic. Make sure to tape the "blanket" up good leaving nowhere for sound to escape. You can then set a pillow under the fan /blanket for vibration suppression. It worked great for me.

thanks for the input man, but i'm aware both of the advantages of inline fans and sound reduction techniques.
my question was more budget-related; i don't want to throw money away, and i'm not looking to spend more than £30 max per fan (i need two because mine are shite)...
anybody got a model to recommend? 400w and 600w cooltube ventilation btw.. smallish growrooms (1.4mt2 total) so power is important...