I have 5 males in my cage and they don't smell at all. I floored the cages in lino so nothing holds the urine smell, (plus it is soooo easy to just pull out the lining, wipe it, stick it back in) and just change their hammocks every day. :) If you are looking to save money on bedding for the males, definitely try lino. I know the nursing and pregnant females need the bedding for making huge nests, but the guys will be happy with just a digging box and/or nest boxes.
I love my ratties. Cutest, cleanest, sweetest, funniest, most intelligent little pets you could ever wish for. :)