how do you sneak a cat by a landlord?

i don't want to pay hte $150 non refund and $150 refund and $15 a month for my cat. the way apartment complexes charge tenants is highway robbery if you ask me! i've had my cat for 1 1/2 years now, and am completely attached to him! i can't afford the rent and deposits, but i cant get rid of him.