Treating the question with a seriousness that it probably doesn't deserve...The participants in porn are not paying to have sex, they are being paid to act on film. Their scenes happen to include sex.
I've always wondered why this isn't used as a way to legally have prostitution in areas where prostitution is illegal. Take Kalifornia for example. Ironically, since this is a gun forum, guns are the example. Front Sight Firearms Training Institute originated in Kalifornia and is still based there. Us private citizens can't own Class 3 weapons there. 'Ol Piazza figured a way around the law. He rented a bunch of MG's from a movie supplier (Stembridge?) and had their guy on hand while a bunch of guys had fun shooting. I'm not sure, but I believe he had a video camera so that technically they were using the weapons to make a movie.
The trick (as a pimp) would be to supply the girl and the location. The john would sign a contract to produce a porno film. He pays the director (the pimp) and the actress (the prostitute) and they film their little session. He goes home with the video and technically, an act of prostitution has not occurred.
The problem fight4yourrights, is that you are confusing morality with legality. Morally, there may be little or no difference between pornography and prostitution, but legally...