How do i paint my Buzz Lightyear?

Hello everybody! I want to repaint me signature Buzz Lightyear to he a more accurate color. I dint have professional stuff and i want to spend the least pissible. Can i just sand it, and paint it wirh arcryl paint? Is there a specefic one? Do i need to put a protective layer on it after and wich one? Can i do it with a brush or with a sponge?

Thankyou!!