If I were to go up to a girl, point at my friends, and tell her that "they bet me 10 dollars I couldn't get the prettiest girl on campus to give me a kiss". Do you think she would kiss me? Or would I need to ask if I can kiss her?

Well it depends, is she the real loose kind that laughs and has a smile on her face? 

Or is she the real, 'I'm Popular, I am too amazing for any of this.' If she's like the Popular kind, she would probably not go for it, unless you probably are one of the hottest guys on campus. If she is loosey, then go for it! 

I know a girl that is both, for some reason, it gets me real confused. So yeah!

Just as the previous answer was, it really depends on the girl. But there are more than just two types of girls.

So if this girl is super popular but pretty nice, then she'd probably just giggle and would say something like "stop playing". She'd most likely not kiss you because her friends will probably here something about this later on. If she's the mean popular kind, then she'd just think you're a loser and would probably ignore you or tell you that you're a creep and get lost.

If this girl is a shy or a shy smart girl, she'd most likely just look at you weird or confused. She'd probably also blush. But there are some smart girls who are sarcastic and they'd probably also roll their eyes and say something snarky like "looks like you're friends will win". The mean smart girls would most likely do the same thing as the mean popular girls because they would think that you are stupid. Out of all the girls in this paragraph, the smart sarcastic one would be the most likely one to kiss you though.

If you're dealing with someone who is the happy, cheerful, super nice kind, they'd just laugh, probably will say thank you, but won't kiss you. Either that or she'd be really creeped out and not know what to say since she doesn't want to be mean.

The girls who would probably kiss you without you asking are the daring kinds or the ones who are quite well known for being pretty loose about this type of thing. Usually these girls have a reputation for being this way or are trying to build that type of reputation up. They will also most likely be the kinds who are pretty despserate to do anything related to a guy but don't really have a high social status or are religious. Other than that, you probably would have to ask and most of them would either just kiss you on the cheek, say that it's not appropriate, or flat out say no. But you never know, you might get lucky!