Realtek SDR (Software Defined Radios) made out of DVB-T TV tuner cards for $11-$20 on eBay or Ama...

[G+_Red Penguin]

Realtek SDR (Software Defined Radios) made out of DVB-T TV tuner cards for $11-$20 on eBay or Amazon.

 

Allows you to listen to everything from the FM broadcast band to police traffic on your PC.

 

A video of it in action:

 

 

Some more explanation:

 

http://www.rtl-sdr.com/about-rtl-sdr/

 

You can also hook it up to an Android via USB OTG and run it as if it was on your PC or run it over the network on a PC or RasPi and connect your Android or other devices to it.