Independent Arduino power supply - 5V from batteries


I've read some posts here and online about how to power the 5V of the board. I aim for it to work without being connected to the USB of the laptop, so I'm trying to figure out the best way to power it, without ruining something.

From what I understand connecting directly to the 5V or 3.3V pin is a no-no. I know that I can get a DC of 7-12V and connect it to the DC input of the board, but that means I will still have to find a socket, and the board won't function in a portable way.

I am currently powering a servo motor using four 1.5V batteries together, to get the exact 6V I need for it.

Is it a good choice to get some batteries and connect them in the same way to reach 5V?

Any ideas would be welcome. Currently I can't think of a voltage that will add up to exactly 5... with 1.2 I will get only 4.8...