The amount and type of pet deposit you will have to pay varies by your landlord. Some apartments charge a pet rent fee of $35-$50 per month in addition to your rent. Some landlords charge a one-time pet deposit of $250 per pet. Make sure you understand the details of your pet deposit, and whether it's refundable or not. Some landlords will keep your pet deposit plus charge you for any damages in addition to that. Read your rental agreement closely to avoid a misunderstanding.