Matt Laur , Jul 04, 2009; 07:06 a.m.
I hope you don't mind if I'm totally frank, here. At $15, you've already wasted your time. For that sitting fee, you're better off not charging anything, and simply charging on delivery of prints/CD/whatever-you're-delivering.
$15 is very low. For the time you put into getting ready to shoot, meeting up, taking the photographs... you're talking about a fraction of minimum wage. That sets your expectations and hers very low - and that can fuel the immediate reactions that people get when they see an un-edited shot on the back of a camera.
Since you're already not making any money on the sitting, you'll earn something far more valuable than $15 by offering to re-shoot. You'll learn some more about how to deal with heavier, self-conscious people. You'll learn how to spin a customer relations problem to your advantage. You'll learn not to chase the customer off to "other photographers" (are these other folks also charging so little, or is she going to re-think her budget and hire a pro?). And most importantly, you'll be buying, with that extra bit of work, some good will. This sort of work is almost entirely about word of mouth. You get or lose the next opportunity that way, more than any other way.