Why pay when I can score for free? 
People go broke trying to get it "for free". Depending on how often you're scoring "for free" and how many of those times are On The Margin for you, you might want to re-evaluate the puritanical stigma against prostitution as simple idealistic propaganda and go for a potentially more economical choice.
For some of us, of course, paying for sex from a woman of the caliber we would prefer is far less economical then just getting it "for free".
Don't be afraid of the math!