Really, really want a pet hamster?

I really, really want a pet hamster of my very own. I love my 2 dogs, but I want a pet that's adorable and little and sweet. My mom already said I can get one, but we are both a little wary about the care and habits of the little guys. I do attend school so I'd want it to be okay while I was gone. If necessary, my mom also said that I could get 2 to keep each other company. I really am worried about biting and fighting though. So, basically I'm looking for a little hamster that is friendly and easy to care for. Which type of hamster should I get? And if I need to get 2, which genders should I get(I want a female but I don't want her to have babies). Please help me! Thanks in advance :)