In campaigns and challenges and whatnot a good way to save money is to use the grassland biome (most if not all animals are satisfied with it no matter what) and make a lot of mixed exhibits (lions and tigers together, and so on.) I have done this before and was able to keep the zoo going for a long time.

i do this sometimes too, its quite handy in campaign mode.
thoughi usually try to put all hebavores together and then some carnivores together

How Do Get all of those horses? ( I must know or ill go CRAZY!!! :hyper: )