What Is "Channel 3?"

Simply put, it's any 2-way radio with a standardized #3 channel.
An old-style (but effective!) Citizen's Band radio, a bubble-pack walkie talkie from WalWorld, a GMRS radio from a sporting goods store, a MURS radio (usually a business band), or a locally pre-programmed Amateur (ham) radio. 
RADIO TYPE         CHANNEL     FREQUENCY
– CB                              3                26.985 MHz
– FRS/GMRS               3                462.6125 Mhz
– MURS                        3                151.940 Mhz

amrron.com/communications-resources/ch3-project/
We have the  resources and folks to program your ham radio, free,  at local meetings that occur twice a month.  More on that later.  Just know that, if you don't already have a comm device, you can get started with as little as $30.  Drop an email, see how easy & fun it is!
KI7BIV