right motor for props.

Hi all,
I'm starting to learn arduino, and I have a ""crazy"" project on my mind.
I'd like to make a mei's snowball robot (not very advanced like the one you can see on yt), I just want to make this little spherical cap to rotate clockwise and counter-clockwise and power on some led.
As for the led + arduino there is no problem.

The problem comes with the motor!

There is dc motors, servo, stepper, what motor should I buy to this project? I don't know how much power I need for rotation but the prop isn't so heavy.
Does I need gears too?
Oh and one last thing...I need something cheap lol

Thank you in advance

Depends on a few factors:

a) what level of accuracy are you looking for? Do you need it to stop at exactly 32 degrees for example? or simply just know where its 'home' location is and rotate left/right?

b) how fast do you want it to move?

c) how heavy do you anticipate it being?

and how many degrees of travel? (servos are typically only 120 degrees)