One thing I did when I was unemployed was to go into the Pet Food Stores and take the free sample bags they had on display there.
I wasnt greedy, and tried to rotate the stores as much as possible.
I think thats why the Found Cats are not fussy, as they would have different foods every day.
Call the Cat Food Companies and watch the Flyers for deal, thats how I feed All The Found Cats on a fixed income.