Really, why all the interest? I don't find her attractive in the slightest, although I could see how some might.
I think there reaches a point where it just becomes about power games; far less about her and more about who has the biggest metaphorical penis. The men bidding are by now just trying to prove who's more manly, I suspect. When it gets to these sums of money, it's about far more than just sex.
Ethically, I don't see the problem with it myself. The selling of sex acts isn't something I find offensive, but the attitudes and conditions that they often take place in are the problem. If a man or woman bought sex with someone and then viewed that they had some kind of 'ownership' or power over them, then I'd have an issue with it. The fact that most prostitutes are trafficked, abused and live in horrible conditions is why I see it as an issue. Mostly, I just find the fetishisation of this girl's virginity really rather creepy.