1. You would NOT have to spend one single second in jail just so you could challenge the constitutionality of a prostitution law. To have "standing" (the right to be a party to a case), all you have to show to challenge a statute is that you are or could be subjected to the provisions of the statute. That's usually not too difficult to show. So you may have to blow a judge to prove that you're in the sex industry, but at least you won't have to go to jail! (Note for those a little slow on the uptake: You wouldn't actually have to give a judge a blowjob...probably

)
2. Lawrence v. Texas pretty clearly says there is a privacy right only in "consensual,
non-commercial sexual conduct"....so I still don't think Lawrence is the way to argue your case, at least not the entirety of it (though if any other lawyers on the board have a different opinion I'd be happy to hear it). In my opinion this is a Commerce Clause issue, and your argument would be something like "the legislature is unfairly and overzealously criminalizing a market, to an extent that has a profound effect on my livelihood, for no compelling reason."
That's the basic outline. Someone much smarter than me could come up with something much stronger I'm sure.
3. Yes, expenses for this little hypothetical crusade to the Supreme Court would be expensive. BUT!...would that
really be a problem for you? If you got the word out that you were trying to legalize prostitution in the U.S. (or even just Texas), you'd have funds flying in. Set up a KickStarter page! Have a Sexy car wash! You could offer a Supreme Court Edition BnG Marathon for $250 a pop! You could cover the expenses with one solid month of marketing/working