Monthly costs will be for food, litter, tsotyhen you have to decide if you are going to do a combination of wet and dry catfood or just dry or just wet? you will need a litter box and litter to fill it with and a scoop to clean it daily with.i would also suggest getting nail clippers and a scratching post/board and a ****** gun, when the cat is caught on tabletops or where not alloweed, ****** it so the cat doesnt know where it came from, after a few times, they will stay off that area, as far as breakables, cats are pretty gentle, but i would remove anything that could be broken until you learn what the cat will do and act, they are all very individual attitudes and personalities! Good Luck!