Well, let's see. I have two cats and just switched over their food to Royal Canin. That was a 3.5 lb bag (I *think*, not sure. I know it was the smaller of the two.) and it cost 14.96 plus 8.6 percent tax. They only get treats sporadically mainly because they are picky and don't really like anything except Whiskas Temptations (three dollars for a small pouch) and some moist treats (two dollars per pouch, ever other month or so). Litter (Feline Pine) is $20 for the bag that we just got. It's a huge bag, though. So... it works out to be 40.23 for this month, I believe.

Edit: This bag of FP should last for a month and a half or so.