I still feed CSFTDLS from time to time when I get lazy, and I think a 20-something pound bag is around $20.99. I think Canidae is around 40 lbs for $35.99. I'm not too sure about this and the prices might fluctuate from area to area, but this is a good guess.

However, that 20-something pound of CSFTDLS lasted Giselle at least a month, so if you think about it that's less than a dollar a day. I'm sure Roxy doesn't eat as much/more than Gissie because Roxy's rather sedentary and much smaller in size, so that 20-something bag is going to last you at least a month.