I've been doing the Emerald Isle Dailies. The reward bags can have 0-5 plat and a few other items in them. Doing that on one 5 box team can generate anywhere from 60-100p a day. I don't even bother with the onslaught dailies.

I also sell the artifacts and augments I get from invasions. I get so many of these things that the toughest part is making time to AH them.