What are the different sizes in lip piercings?

im thinking about getting a lip piercing, and i don't want some huge chunk of metal sticking out of my lip, i just want a small stud or a thin ring. i was wondering what the different sizes and options are when it comes too lip piercings? also, what is the best too get if i end up not wanting it a year later and i want it too close up neatly? would it leave a noticeable scar? thank you!