I use the StayFree Maxi Deodorant pads for their belly bands. The pads are super absorbency and since they are scented they keep them smelling clean longer. I also use Baby wipes, the scented and wipe them everytime I change their pad. On top of that I have a feminine spray that I spray them as well.
Between everything it keeps them smelling fresh and clean rather than that pee smell.
Oh and the pads I get are $3 for 24 pads. I change them about 3 times a day.