Whether you are renting a house or renting an apartment, you will no doubt be faced with having to pay a Security Deposit. A security deposit is a way for landlords to protect their investment whether it be for unpaid rent or for damage the tenant may cause to the property. It covers hiring someone to paint, materials, new carpets if necessary, and a multitude of other things that could happen while the tenant resides on the premises that is considered above and beyond normal wear and tear.
So, you might be wondering how much of a security deposit you should expect to pay. Every state has its own laws. A common practice in many states is require a deposit of one to two month's rent. There are others where you will find that they word it different to say that to move in you have to pay first and last month's rent. Always check the laws in the state the residence is in to find out what you could expect as some have limits, some don't. Also, some states require the security deposit to be placed into an escrow account and some others require that interest be paid above a certain security deposit amount. These are things you NEED to know. A great site for reference is http://www.nolo.com/legal-encyclopedia/chart-29020.html.
A few additional suggestions to make sure you are covered. Take time/date stamped pictures prior to moving your stuff in to show anything that might be construed as damage on your part. You will also want to always complete a walk through, notating anything that might come into question later, and have the landlord sign off on it. And always, and I do mean ALWAYS, get a receipt!