Hey, this might be a little vague but i'm looking for a AH highschool fic where Buffy thinks she is popular but really isn't, and Spike is really popular. I'm pretty sure Buffy doesn't like Spike either. Anyway, Spike makes a bet with Buffy, but i'm not sure what for. All I know is that in order to win, Buffy must ask 3 (i think) guys to go on a date with her and at least one of them has to say yes, and Spike has to do the same. Spike gets all 3 girls to say yes, and Buffy gets turned down by all 3. I think it's a one shot as well?? Thanks!

I think this is the one you're looking for:

The bet by scarlet845
Summary: Spike Giles, an incredibly handsome and popular high school senior, has picked on dorky Buffy for years because she's under the delusion that she's popular as well. All of this changes when he challenges her to a bet where he agrees to leave her alone forever if she can get just one guy in school to go out with her.

http://spikeluver.com/SpuffyRealm/viewstory.php?sid=10642&ageconsent=ok&warning=5

That's the one! Thankyou so much!!!