I think, in general, a guy would want to get to know a cute girl and so they would take them on a 'date' to get to know them better, spend a little time, maybe get a cuddle.
To sweeten the deal usually the guy would offer to pay to help reduce the chance of getting rejected.
Once you are in a relationship the dates then become half/half but I think the inital set of dates (3 or 4) maybe more depending on the attractiveness of the guy vs the attractiveness of the girl, would be paid for by the guy.
I think if you are 'dating' then it would be more then just sex, now on the other hand for nightclubbing, the guy will almost always buy the girl a few drinks to get to know them and .... well, you can guess the rest.