My father wants to take to a prostitute

I've been 18 since september of last year. Today, out of nowhere my dad said that he'd pay for me to lose my virginity to a prostitute. 

I don't know how other people would react to their dad saying that to them, but personally I didn't know what to say. At first I was shocked, then angry that he would think I would have to resort to that at my age, but more recently I've just been feeling like shit for the past few hours. I can't seem to enjoying the things I usually do for leisure, like video games or music without thinking about what he said.

It should be noted that I am not completly naieve of sex. I learned about it and all the precautions to take in school, and I masturbate regularly to pornography. Also I am entirely comfortable with my heterosexuality, as well as the sexuality of others.

I don't mind that the sex in porn isn't realistic. It's merely just fetish fodder. I just don't want my first time to be paid for, "cheapening" the experience. Even if it isn't me who's paying.

I wanted to tell him over the phone to make it easier, but I couldn't reach him. :(

Please tell me what you think about my situation - I would like male and female perspectives. How would you tell him? (I don't want to it seem akward for not accepting)

Also I'm not being a prude saying that prostution is completly wrong. I just don't want anything to do with it.

If something similar happened to you, did you go through with it or not, and why?

The second question is out of interest. I already made up my mind. I'm saying no.