The extra food bowl comes with it, but just clips on so if you don't want it, just throw it away. I don't use mine, except when I fill it with breath freshener and then I attach it for an hour or so until I make sure that they all drink a little to keep their breaths sweet.
The mat is sold separately, and is about $15-$20. Some places I have seen online sell it with the mat. I bought the mat a while back because our floor is really uneven and it was sitting strangely, but other than that I wouldn't bother.
I would recommend not getting the economy fountain if you don't want to fill it all the time as it holds a lot less water. Also there is a dog-it one in red (which is the exact same as the cat-it just a different colour, sometimes it is easier to find the filters for the dog-it, but they are the exact same!)