My son's aunt, who lives downstairs from me, is going to her prom on Friday. She's going w/ like 4 or 5 couples. Her mom asked me if I would be home to shoot some pics for her. I said fine. I figure, I'll also shoot for the couples too. Then put them up on my website and give them my business card and if they want to buy them, then they can buy them from my site. I don't really need any tips for shooting them, but rather on how much to charge. Since I won't be charging a "sitting fee", I need to adjust my a la carte price accordingly. What's typical for 8x10, 5x7 and wallet size?