If you own a smart phone, then you probably love finding great apps to play. But if you purchased an iPhone or iPod touch, then you probably don’t have a lot of money left over to buy apps.

Luckily, there are few feelings better than discovering something that is fun, easy to use and free. 5-0 Radio is a free app that comes pretty darn close to offering this sought-after trifecta. Developed by New & Popular, the app turns your iPhone or iPod touch into a police scanner. Depending on your personality, this will lead to hours or minutes of good times.

The 5-0 Radio user interface is clean and simple. A list of menus provide the option to browse through scanner feeds from police stations nationwide. Users can browse the top 100 police feeds (most of which come from big cities), add your own feed, or even search the web if you can’t find a feed from a police department near you.

After a station is selected, 5-0 Radio offers another set of options to help users eavesdrop on the fuzz. The most useful item on the menu is a glossary of codes and jargon used by emergency responders and police officers. This small addition is really helpful because it helps the average user to keep up with what’s happening on the police scanner even if they don’t know the lingo.

The quality of the police scanner feeds are another area in which 5-0 Radio excels. When I tested it on my local station, the audio feed came through crystal clear.

The biggest weakness of 5-0 Radio has nothing to do with the app. It’s the subject. After a while, most police calls are just boring. This isn’t an episode of “COPS.” It’s raw, unedited police feeds. For small towns this means, a lot of waiting around for something to happen, a few cats stuck in a tree, and maybe a call about some “punk kids” from the grumpy old neighbor down the road. Most listeners will probably lose interest rather quickly.

Police scanner aficionados will love 5-0 Radio and listen for hours. (If this is you, remember to plug your device in to a power source so you don’t kill the battery.)

Listeners that don’t find enough action in their home town, can also tune in to a selection of police feeds from across the United States.

The other drawback of 5-0 Radio is it requires a WiFi connection. Since the iPhone and iPod touch don’t have a radio transmitter built in, the app works by accessing available Internet feeds from police stations that broadcast over the ‘net. 5-0 Radio doesn’t work with the 3G network.

There is also a paid version of 5-0 Radio for $0.99. The premium version adds a music scanner so users can to listen to Internet radio between police calls.

Whether you get the lite version for free or shell out the $0.99 to go premium, 5-0 Radio is an interesting app that offers something new to listen to while you’re waiting in line at the grocery store.