BEFORE you sign a lease on a unit, inspect the unit. Should you change your mind after you give a deposit, you may lose your right to a refund and be further liable until the landlord rerents the unit.

Get all agreements in writing and a dated receipt for your deposit. In your lease, be sure to state the date and amount of the security deposit. DO NOT GIVE CASH.

South Dakota places a limit on Security Deposits of ONE MONTHS RENT.

HOWEVER, "special circumstances" may enable the landlord to charge a higher  security deposit. For example, if you have a pet, the landlord may charge you an extra, refundable deposit to cover potential damages from your pet. 

Every lessor of residential premises shall, within two weeks after the termination of the tenancy and receipt of the tenant's mailing address or delivery instructions (NOTIFY YOUR LANDLORD OF YOUR NEW ADDRESS), return the security deposit to the tenant, or furnish to the tenant, a written statement showing the specific reason for the withholding of the deposit or any portion thereof.

The lessor may withhold from such deposit only such amounts as are reasonably necessary to remedy tenant defaults in the payment of rent or of other funds due to the landlord pursuant to an agreement or to restore the premises to their condition at the commencement of the tenancy, ordinary wear and tear excepted. See RentLaw.com for Normal Wear and Tear

Any lessor of residential premises who fails to comply with this section shall forfeit all rights to withhold any portion of such deposit.
The bad faith retention of a deposit or any portion of a deposit by a lessor of residential premises in violation of this section, including failure to provide the written statement and itemized accounting required by this section, shall subject the lessor to punitive damages not to exceed two hundred dollars. (Amount subject to change or decision by a court)