Wow, I've really appreciated all the advice, from everyone.
First, I've decided not to go to the party. I called the people who run the party, and they seem like really cool people, and answered alot of my questions (like do I have to participate). Ultimately, I feel like as a single female, I really want to go as a single female. I'm not with a man, I don't want to be with one, and just like one of y'all said, I'm really there as his "ticket" and he's most likely trying to hook up with someone else there, so what's the point?
I'm glad y'all agree that its weird for a guy to offer to set up a party for me, in exchange for sex. After that, I didn't feel bad at all for telling them "no thanks"
I think I'll take this at my own pace, and maybe go to one of these parties on my own...
Thanks again!