The reason I don't want to solder is that I screw it up (idk, maybe I was doing it wrong) and I can't reuse the parts. Thanks crossroads, but the problem that the space between matrix pin lines is as wide as the whole breadboard. I guess I'll just wait for my breadboard... What about power? I know, it's a stupid basic question, but anyway; does a led/matrix/buzzer/any device connected to arduino take whatever current it needs or what?
A LED matrix usually needs a lot more current than the Arduino can provide.
For example: depending on the color, a LED can take from 20mA to 40mA. Lets average that to 30mA.
If you decide to light up all the leds in your matrix, you'll need 64 x 30mA = 1,92A That is right: almost 2 amperes. that is more than enough to fry the voltage regulator in the Arduino board. That would be 10W of power the little voltage regulator of the arduino would have to dissipate.
What LED drivers (like the MAX7219) do is to PWM the rows or columns of LEDs to keep the current low. That is pretty clever of them. For us, it seems that all LEDs are lit, but the driver is PWMing them really quick.
One Arduino can power a LED matrix and the MAX7219 and still light up all the LEDs. That can't be done without the driver.