The way I see it, prostitution is damaging to women because it reduces the value of sex to its fair market value. It reduces women's bargaining power. A man who would like to have sex with a woman of certain parameters (say, blonde, blue eyes, hourglass figure) no longer has to engage in a long term relationship with a woman, and bear its significant financial burden. He can get a prostitute that caters to his taste, for much cheaper, and with no long term "contract".
The way I see it, this is the secret motivation of every anti-prostitution participant in this thread. They don't like the idea of men having this option.
A victim of human trafficking is not a victim of prostitution. Nor is such victimization any sort of collateral damage, it is direct. Furthermore, the legalization of prostitution will reduce human trafficking (and therefore victimization by it) by providing a safer and higher quality alternative in any and all cases.
I thought it was obvious, but I'll spell it out for you. A worldview that would seek to ban all employment without proposing some alternative method of partitioning the world's limited resources is nonsensical.
At that price, I wouldn't risk free.