Yes there are. Canon hasn't changed its cartridges for at least two years (they have only three different systems: the regular 4 ink line (most printers, also the i550), the 6 ink systems for all photo printers, and the professional line (N1000, N2000, etc., professional ink jetters).
There are generic cartridges from a lot of companies. Although the original Canon ones are cheaper than the generics of the other companies. Generics are no problem, except for black. In my experience, generic black tends to flow into yellow (looks ugly for presentations).
My S630 has been a very reliable printer, very fast with good looking results.