HotPads Rentals & Real Estate This app is great because it works with GPS to create an interactive map of available apartments in your area that you can click on to communicate with the realtor/company/manager/etc. It can also be helpful in determining a reasonable price point in your neighborhood. It also lets you know how long a listing has been up, so if you see a building that's pretty empty and has a lot of listings that have been open for weeks, that might be a useful clue about place to avoid.

Apartments by ForRent.com The main reason I downloaded this app was because I have an acquaintance who successfully found their apartment using it. It has some nice features, and is also a good supplement if you don't want to have to throw yourself into the craziness of craigslist.

Apartments Let me say it up front: It's hard for me not to focus on NYC because it's where I live. But I do realize other people in other cities need places to live too, so I'm trying to include apps that will work in a variety of markets. While I'm not always super impressed with the individual listings on this app, it does tend to give one a good idea of the prevailing prices within a certain radius and the kinds of amenities you can expect in your budge range.

freecreditscore.com One of the most important numbers when you're renting an apartment is going to be your credit score. This app partners with the full website to give you a snapshot of your score.